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LYMPHOMAS- GITDRARIFKHAN S
GI LYMPHOMA
CLASSIFICATION SYSTTEMS
PET CT
Introduction
GI lymphoma is uncommon
Extraa nodal involvement GI is more common other site include spleen thymus to brain soft tissue
Non Hodgkinrsquos type almost exclusively
Primary gastrointestinal involvement the stomach
can involve any part of the gastrointestinal tract from the esophagus to the rectum
19 in 100000 a male-female ratio of 32
Risk Factors
HIV infection
Helicobacter pylori infection
immunosuppression after solid organ transplantation
Celiac disease
inflammatory bowel disease
human immunodeficiency virus infection
Criteria for diagnosing primary Extranodal lymphoma
1 No palpable superficial lymph nodes are seen
2 Chest radiographic findings are normal (ie no adenopathy)
3 The white blood cell count (both total and differential) is normal
4 At laparotomy the alimentary lesion is predominantly involved with lymph node involvement (if any) confined to the drainage area of the involved segment of gut
5 There is no involvement of the liver and spleen
Frequency of GI occurrence by site(of all lymphomas)
Stomach
Small intestine
Rectum
Rest of colon
Role of imaging
Most common modality is CT helps in assessing the stage of disease
a wide variety of imaging appearances and definitive diagnosis relies on histopathologicanalysis
Pointers in Imaging
a bulky mass or diffuse infiltration
with preservation of fat planes and
no obstruction
multiple site involvement
associated bulky lymphadenopathy
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
GI LYMPHOMA
CLASSIFICATION SYSTTEMS
PET CT
Introduction
GI lymphoma is uncommon
Extraa nodal involvement GI is more common other site include spleen thymus to brain soft tissue
Non Hodgkinrsquos type almost exclusively
Primary gastrointestinal involvement the stomach
can involve any part of the gastrointestinal tract from the esophagus to the rectum
19 in 100000 a male-female ratio of 32
Risk Factors
HIV infection
Helicobacter pylori infection
immunosuppression after solid organ transplantation
Celiac disease
inflammatory bowel disease
human immunodeficiency virus infection
Criteria for diagnosing primary Extranodal lymphoma
1 No palpable superficial lymph nodes are seen
2 Chest radiographic findings are normal (ie no adenopathy)
3 The white blood cell count (both total and differential) is normal
4 At laparotomy the alimentary lesion is predominantly involved with lymph node involvement (if any) confined to the drainage area of the involved segment of gut
5 There is no involvement of the liver and spleen
Frequency of GI occurrence by site(of all lymphomas)
Stomach
Small intestine
Rectum
Rest of colon
Role of imaging
Most common modality is CT helps in assessing the stage of disease
a wide variety of imaging appearances and definitive diagnosis relies on histopathologicanalysis
Pointers in Imaging
a bulky mass or diffuse infiltration
with preservation of fat planes and
no obstruction
multiple site involvement
associated bulky lymphadenopathy
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Introduction
GI lymphoma is uncommon
Extraa nodal involvement GI is more common other site include spleen thymus to brain soft tissue
Non Hodgkinrsquos type almost exclusively
Primary gastrointestinal involvement the stomach
can involve any part of the gastrointestinal tract from the esophagus to the rectum
19 in 100000 a male-female ratio of 32
Risk Factors
HIV infection
Helicobacter pylori infection
immunosuppression after solid organ transplantation
Celiac disease
inflammatory bowel disease
human immunodeficiency virus infection
Criteria for diagnosing primary Extranodal lymphoma
1 No palpable superficial lymph nodes are seen
2 Chest radiographic findings are normal (ie no adenopathy)
3 The white blood cell count (both total and differential) is normal
4 At laparotomy the alimentary lesion is predominantly involved with lymph node involvement (if any) confined to the drainage area of the involved segment of gut
5 There is no involvement of the liver and spleen
Frequency of GI occurrence by site(of all lymphomas)
Stomach
Small intestine
Rectum
Rest of colon
Role of imaging
Most common modality is CT helps in assessing the stage of disease
a wide variety of imaging appearances and definitive diagnosis relies on histopathologicanalysis
Pointers in Imaging
a bulky mass or diffuse infiltration
with preservation of fat planes and
no obstruction
multiple site involvement
associated bulky lymphadenopathy
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Risk Factors
HIV infection
Helicobacter pylori infection
immunosuppression after solid organ transplantation
Celiac disease
inflammatory bowel disease
human immunodeficiency virus infection
Criteria for diagnosing primary Extranodal lymphoma
1 No palpable superficial lymph nodes are seen
2 Chest radiographic findings are normal (ie no adenopathy)
3 The white blood cell count (both total and differential) is normal
4 At laparotomy the alimentary lesion is predominantly involved with lymph node involvement (if any) confined to the drainage area of the involved segment of gut
5 There is no involvement of the liver and spleen
Frequency of GI occurrence by site(of all lymphomas)
Stomach
Small intestine
Rectum
Rest of colon
Role of imaging
Most common modality is CT helps in assessing the stage of disease
a wide variety of imaging appearances and definitive diagnosis relies on histopathologicanalysis
Pointers in Imaging
a bulky mass or diffuse infiltration
with preservation of fat planes and
no obstruction
multiple site involvement
associated bulky lymphadenopathy
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Criteria for diagnosing primary Extranodal lymphoma
1 No palpable superficial lymph nodes are seen
2 Chest radiographic findings are normal (ie no adenopathy)
3 The white blood cell count (both total and differential) is normal
4 At laparotomy the alimentary lesion is predominantly involved with lymph node involvement (if any) confined to the drainage area of the involved segment of gut
5 There is no involvement of the liver and spleen
Frequency of GI occurrence by site(of all lymphomas)
Stomach
Small intestine
Rectum
Rest of colon
Role of imaging
Most common modality is CT helps in assessing the stage of disease
a wide variety of imaging appearances and definitive diagnosis relies on histopathologicanalysis
Pointers in Imaging
a bulky mass or diffuse infiltration
with preservation of fat planes and
no obstruction
multiple site involvement
associated bulky lymphadenopathy
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Frequency of GI occurrence by site(of all lymphomas)
Stomach
Small intestine
Rectum
Rest of colon
Role of imaging
Most common modality is CT helps in assessing the stage of disease
a wide variety of imaging appearances and definitive diagnosis relies on histopathologicanalysis
Pointers in Imaging
a bulky mass or diffuse infiltration
with preservation of fat planes and
no obstruction
multiple site involvement
associated bulky lymphadenopathy
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Role of imaging
Most common modality is CT helps in assessing the stage of disease
a wide variety of imaging appearances and definitive diagnosis relies on histopathologicanalysis
Pointers in Imaging
a bulky mass or diffuse infiltration
with preservation of fat planes and
no obstruction
multiple site involvement
associated bulky lymphadenopathy
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Imaging also plays an important role in the detection of complications such as perforation obstruction and fistulisation
However advanced lymphomas arising in the gastrointestinal
tract may eventually disseminate widely and be clinically
radiologically and pathologically indistinguishable from secondary gastrointestinal lymphomas
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Staging
stage I tumor confined togastrointestinal tract single primary site and multiple noncontiguous lesions
stage II tumor extends into the abdominal cavity from the primary gastrointestinal site
(II1 local nodal involvement
II2 distant nodal involvement
Stage III penetration through serosa to involve adjacent organs or tissues and
stage IV disseminated extranodal involvement or a gastro-intestinal tract
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Esophageal Lymphoma
Secondary to cervical and mediastinal lymph node
Contiguous spread from gastric lymphoma
Primary lymphoma of the esophagus is a rare condition
Primary esophageal lymphomas are predominantly B-cell type (recent reports diagnosing MALT lymphomas)
RADIOLOGICAL FEATURES
Submucosal infiltration or polypoid mass
With ulceration or nodularity
Barium studies subtle mucosal and submucosal abnormalities
CT better defines the extent of local disease and the disease stage
Perforation and fistulisation can also be sen in CT and barium studies
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Gastric lymphoma
Comprises 3-5 of all gastric neoplasms
bull Non-Hodgkinrsquos accounts for 80 of all gastric lymphomas
bull Begins in the submucosa
bull Most occur in distal body and antrum of stomach
bull Almost all gastric lymphoma presents with some degree of ulceration
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Pathology
Three distinct types of gastric lymphoma
low-grade MALT lymphoma 60 of all primary gastric lymphomas
primary sporadic lymphoma vast majority are B-cell non-Hodgkins lymphoma
secondary involvement of the stomach by systemic lymphoma (usually high grade)
Chronic H pylori gastritis is associated with the development of low-grade MALT Lymphoma having been reported to account for 50ndash72 of all primary gastric Lymphomas
MALT lymphoma is treatable and has better prognosis in early stages
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Nodularmdashsingle or multiple intragastric masses easily confused with Ca
protrude into the lumen often with multiple ulcerations
Polypoidmdashbarium in interstices frequently with ulceration sometimes resembles metastatic disease such as melanoma
Ulcerativemdashshallow saucer-like ulcer indistinguishable from Ca
Infiltrativemdashthickened irregular folds simulating the appearance of hypertrophic gastritis about 10 present this way
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Radiographic features
Fluoroscopy barium meal
Appearances vary from normal to grossly abnormal
bulls eye appearance due to central ulceration
filling defects
thickened gastric rugae
linitis plastica
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
CT
marked thickening of the stomach wall (2-4cm)
extensive lateral extension of the tumour (ie along the wall of the stomach) representing submucosalspread
submucosal spread encompasses the majority of the stomach giving it a linitis plastica appearance
uncommon for lymphoma to result in gastric outlet obstruction
Rarely cause perigastric fat invasion
homogeneous in attenuation but may contain focal areas of low density representing necrosis
Extensive retroperitoneal and local nodal enlargement
Complications such as obstruction perforation or fistulisation can occur as a result of the disease itself or of treatment and can be detected with CT and barium studies
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Differential diagnosis
gastric carcinoma
more likely to cause gastric outlet obstruction
more likely to be in the distal stomach
more likely to extend beyond the serosa and obliterate adjacent fat plane
more focal
lymph nodes tend to be smaller and more localized to immediate draining nodes
gastrointestinal stromal tumour (GIST)
For diffuse gastric wall thickening also consider
gastritis
Menetriers disease has a rugal like pattern
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Small Bowel lymphoma most common malignancy of the small bowel ( 17-30 of all )
related to B-cell hyperactivation in HIV positive patients
The distal ileum is classically thought to be the most common site
A circumferential bulky mass in the intestinal wall
Predisposing conditions
AIDS
coeliac disease
organ transplant ( post transplant lymphoproliferative disorder (PTLD)
Helicobacter pylori positive patients
Can present clinically as Gi haemorrhage perforation obstruction
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
TYPES
The type of lymphoma depends on the underlying predisposing condition
H pylori mucosa-associated lymphoid tissue lymphoma (MALToma)
PTLD polyclonal B-cell non-Hodgkins lymphoma (EBV associated)
HIV B-cell non-Hodgkins lymphoma 3 overall most common type
T-cell lymphomas are seen but are uncommon 5 they have more perforation
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Infiltrating form
the most common type
focal or diffuse thickening of the bowel wall with alternating areas of dilatation or constriction of the bowel lumen
Folds in the affected segment are thickened nodular effaced and may show ulceration
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Endoexoenteric form
shows irregular collection of barium due to central ulceration associated with displacement of adjacent bowel loops
Associated mesentericabscess or fistula between the tumor and adjacent bowel loops
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Multiple nodular pattern It is usually seen in T-cell
lymphoma complicating celiac disease and is considered most infrequent
Polypoid form
It causes submucosal filling defect and is often associated with intussusception
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
IMAGING
Typically involves a small segment (5-20cm)
Bowell wall thickening (1-7cm)
Aneurysmal dilatation 30 it occurs due to replacement of muscularis by tumor or infiltration of myenteric nerve plexus
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Luminal narrowing is seen but obstruction is rare
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Peritoneal lymphomatosis from primary gastrointestinal lymphoma is rareWhen involved indistinguishable from carcinomatosis
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Large bowel lymphoma
04 of all tumors of the colon
Colorectal lymphomas constitute 6ndash12 of gastrointestinal lymphomas
Primary lymphoma more often affects the cecum and rectum
Most colorectal lymphomas are non- Hodgkin lymphomas usually of B-cell origin
Mantle cell lymphoma is an aggressive disease that manifests as multiple polyps (lymphomatouspolyposis)
Polyposis may also assosciated with MALT lymphoma
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
IMAGING
Multiple polyps mostly near IC valve
a diffuse or a focal segmental lesion with extensive mucosal ulceration at double-contrast barium enema examination
Colonic perforation (T-cell lymphoma)
Circumferential thickening (with or without ulceration)
a cavitary mass excavating into the mesentery
Intussusception may occur with cecal involvement
Focal strictures aneurysmal dilatation ulcerative forms with fistula formation may be seen
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Primary rectal lymphoma is a rare type of gastrointestinal lymphoma and is clinically indistinguishable from rectal carcinoma
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
MESENTRIC LYMPHOMA
The most common malignant neoplasm affecting the mesentery
Patterns of mesenteric lymphoma at CT
multiple homogeneous masses encasing the mesenteric vessels ldquosandwich signrdquo
large ldquocakelikerdquo mass with low-attenuation areas of necrosis displacing small bowel loops
ill-defined infiltration of mesenteric fat particularly after successful chemotherapy
bulky retroperitoneal adenopathy
ALWAYS ASSOSCIATED WITH SMALL BOWELL INVIOLVEMENT
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
v
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Ann Arbor Staging of ExtranodalLymphoma (Modified)
IE Lymphoma restricted to GI tract on one side of diaphragm
IE1 Infiltration limited to mucosa and submucosa
IE2 Infiltration extending beyond submucosa
IIE Lymphoma infiltrating lymph nodes on same sideof diaphragm
IIE1 Infiltration of regional lymph nodes
IIE2 Infiltration of lymph nodes beyond regional nodes
IIIE Lymphoma infiltrating GIT and or lymph nodeson both sides of diaphragm
IV Diffuse or disseminated involvement of liver spleen lung brain
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
LUGANO CLASSIFICATIONradiological
Stage ImdashTumor confined to GI tract single primary site or multiple noncontiguous lesions
Stage IImdashTumor extends into the abdominal cavity fromthe primary GI site
I1mdashLocal nodal involvement
II2mdashDistant nodal involvement
Stage IIImdashPenetration through serosa to involve adjacent organs or tissues
Stage IVmdashDisseminated extranodal involvement or a GI tract lesion with supradiaphragmaticnodal involvement
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Lymphoma Variants
Burkittrsquos Lymphoma
tumor of B lymphocytes seen
younger patients of less than 30 years of age Ileocecal region is most frequently involved
Large rapidly growing masses with mesenteric lymphadenopathy may be encountered
Mediterranean Lymphoma
Mediterranean lymphoma affects younger persons
There is marked thickening of the mucosal folds with nodules due to massive infiltration by plasma
cells
The unaffected intestinal loops show features of malabsorption in the form of flocculation
segmentation and dilatation
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Multiple Lymphomatous Polyposis
a rare form of lymphoma
multiple polypoid lesions of malignant lymphoma are distributed throughout the GI tract
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
FDG PET
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
INTRODUCTION
extranodal disease
The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease
has increased in the past decade
subtle or absent at conventional computed tomography
Imaging of tumor metabolism is the key to diagnose these sites
2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Uses
To identify the involved sites
To distinguish between lesions (primary and relapse)
Intiial staging (95 sensitivity on ombining with CT as in PET-CT)
Follow up and Treatment response assessment
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Current revised response criteriaIndication of PET CT
PET is routinely recommended for the staging of patients with FDG-avid potentially curable lymphomas
PET is not routinely recommended prior to treatment for incurable non-FDG-avid or indolent histologic subtypes
Midtreatment PET should be performed only as a part of clinical trials
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Principle
3-dimensional metabolic imaging technique that uses a radiopharmaceutical to target a specific physiologic process
FDG is transported into cells and phosphorylated in a similar manner to glucose
FDG-6-phosphate is not a substrate for glucose-6-phosphate isomerase and because FDG-6-phosphate is typically not dephosphorylated in tumors
becomes trapped in the cell and reaches a near equilibrium state at approximately 60 minutes after injection
The positron-emitting 18F isotope to which FDG is linked decays and the emitted positron annihilates after ldquobumpingrdquo into an electron generating 2 511-KeV photons emitted in nearly opposite directions that are detected by the PET scanner
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
defining positive PET findings as focal or diffuse FDG uptake above the surrounding background in a location incompatible with normal anatomyphysiology
the standardized uptake value (SUV) representing the ratio of the tumoral tracer concentration to the average tracer concentration in the entire body
Radiopharmaceuticals
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Equipment
PETCT combines a full-ring detector PET scanner with a multidetector helical
the PET scan is acquired immediately after the CT scan
The images are fused to provide precise localization of abnormal lesions
PETCT provides more sensitive and specific imaging than either modality alone
Radiopharmaceuticals
Radiioisotope (F18 C11 Ga 67 I123 ) linked to a Metabolic substrate or Gas
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
FDG uptake in NHL
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Pitfalls of PET
Caution must be exercised in the interpretation of PET scans
technical limitations
variability of FDG avidity among the different lymphoma histologic subtypes
In the large number of etiologies of false-negative and false-positive results
False positives arise because FDG is taken up in any process associated with increased glycolysis for example inflammation infection granulomatous disease such as sarcoidosis and brown fat
False-negative PET scans may result from lesions below the resolution of the scanner generally 5 to 10 mm
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Conclusion
Uncommon disease
a bulky mass or diffuse infiltration
preservation of fat planes
no obstruction
multiple site involvement
associated bulky lymphadenopathy
CT is the most useful modality in that it provides a better overall assessment of the disease stage
FDG-PET is now considered as a gold standard in pre and post therapeutic evaluation of LYMPHOMas in general
Thank you
Thank you
