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SOLITARY PULMONARY NODULE
DR.BHARAT SINGH DMRD-1ST YEAR
SNMC AGRA
DEFINITION A solitary pulmonary nodule
(SPN) is a round or oval opacity smaller than 3 cm in diameter that is completely surrounded by pulmonary parenchyma and is not associated with lymphadenopathy, atelectasis, or pneumonia.
INCIDENCE SPN is found in 1-2% of all CXR
Geographic variations in the incidence of benign lesions, especially infectious granulomas
No sex difference in incidence
Solitary nodules can occur at all age
CONTI…. Smoking history Prior history of malignancy Travel history - Travel to areas with endemic
mycosis (eg, histoplasmosis, coccidioidomycosis, blastomycosis) or a high prevalence of tuberculosis
Occupational risk factors for malignancy - Exposure to asbestos, radon, nickel, chromium, vinyl chloride, and polycyclic hydrocarbons
Previous history of tuberculosis or pulmonary mycosis
ETIOLOGYCongenital TraumaticBronchogenic cysts hematomaAVM (congenital arteriovenous malformations)Bronchial atresia
Infective NeoplasticTB, round pneumonia Bronchogenic ca. Fungal CarcinoidHydatid PlasmacytomaAbscess MetastasesMiscellaneous Lymphoma Wegeners granulomatosis Adenoma, hamartomaRAAmyloidosis ARTEFACTSRounded atelectasis
SPN - ETIOLOGY 40% of spn are malignant, with other common
lesion being granuloma and benign lesion Benign
80% infectious granulomas10% hamartoma10% non-infectious granulomas, benign
tumours Malignant
25% metastatic75% bronchogenic carcinoma and carcinoid
SIMULANTS OF SPNExtra thoracic artefacts
Cutaneous masses – nipple, lipoma ,NF Bony lesions – island, healing #, sclerotic lesion Pleural tumors / plaques Encysted pleural effusion Pulmonary vessels
MODALITIES USED
PLAIN radiography CT
NCCT, CECT PET WITH FDG-F18 PET- CT FNAC / BIOPSY
TWO ISSUES
Lesion detection
Lesion characterization benign versus malignant
LESION DETECTED ON CHEST XRAY Pick up depends upon experience Over reading/ under reading High Kv – better rate of detection Digital radiographs- allow manipulation on a computer
monitor
Always compare current radiographswith previous radiographs
LESION DETECTED ON CXR
SPNs are discovered first as incidental findings on chest radiographs
The first step is to determine whether the nodule is
pulmonary or extra pulmonary
A lateral chest radiograph, fluoroscopy, or CT of the chest
often helps determine the location of the nodule
>8-10 mm Nodules are identifiable by chest radiographs
Occasionally, SPNs can be visualized at 5 mm in diameter
INTERNAL CHARACTERISTICS
Size
Margin
Calcification
Fat
Cavitation
Air bronchograms or bubbly lucencies
SIZEThe size of the mass is of little diagnostic
valueOnly a small percentage of nodules under 1 cm in diameter are malignent.
MARGIN Small nodule with smooth margin suggestive of benign
but not diagnostic of benign lesionLobulated contour Irregular margin typical malignant lesionSpiculating margin
Adjacent tiny nodules, called satellite nodules, may mimic the appearance of a lobulated and the presence of these nodules is strongly associated with benign nature
SMOOTH MARGIN - BENIGN
CALCIFICATION Suggestive of benign SPN
– Central, solid
– Laminated
– Popcorn -1/3 rd of hamartoma
– Diffuse
Suggestive of Malignant SPN
– 6-14% of malignant nodules are calcified on CT
– Eccentric
– Stippled
SOLITARY PULMONARY NODULECALCIFICATION
A stippled appearance or psammomatous calcification
can be seen in SPNs that are metastases from mucin-
secreting tumours such as colon or ovarian cancers
• Dense foci of calcification or be entirely calcified,
with a pattern resembling that of benign Disease can be
seen in carcinoid, metastatic osteosarcoma and
chondrosarcoma
PATTERN OF CALCIFICATIONCentral = granuloma
Nodule completely calcified = granuloma
Target = histoplasmosis
Popcorn = hamartoma
CENTRAL CALCIFICATION
CAVITATION
SPNs with irregular-walled cavities thicker than 16 mm tend to
be malignant
Benign cavitated lesions usually have thinner, smooth wall
Up to 15% of lung cancers form a cavity, but most are larger
than 3cm in diameter
THICK WALLED THIN WALLED
AIR BRONCHOGRAM Air bronchograms are seen more commonly in
pulmonary carcinoma than in benign nodules
Air bronchograms were seen in approximately
30% of malignant nodules but in only 6% of
benign nodules
Air bronchograms is due to desmoplastic reaction
to the tumour that distort the airway
HAMARTOMA
50% of hamartomas have fat
30% of hamartomas have calcification (popcorn appearance)
Middle-aged adults, slow growth ,90% in intra pulmonary
and within 2cm of pleura
fat is present in the nodule , hamartoma or lipoma become
most likely cause , Metastasis from lipo sarcoma, RCC, may
occasionally contain fat
In patient without prior malignancy, focal attenuation
(-40to-120) is reliable indicator of hamrtoma.
HAMARTOMA
INFECTION tuberculoma:
most common in upper lobe
well defined and lobulated ,
calcification frequent , 80% have satellite leison
Cavitation is uncomman
Histoplasmosis
Most frequent in lower lobe
Well defined / seldom larger than 3cm
Calcification common and central –target appearance
Cavitation are rare
HYADIT CYST
Most common right lower lobe
Common in endemic area
Well defined , 1-10 cm in size
Rupture result in –water lilly sign
VASCULAR AVM: Well defined and lobulated- Bag of worm appearence dilated feeding arteries and draining vein may be visible 66% are single, calcification is rare Hematoma peripheral ,smooth and well defined slow resolution over several weeks Pulmonary infarction Most frequent in lower lobe wedge shaped area of consolidation can be identified abutting the
pleura , small u/l or b/l pleural effusion is seen
AVM
AVM WITH FEEDING VESSELS
CONGENITAL Pulmonary sequestration
usually more than 6cm in diameter 2/3rd in left LL ,1/3rd in rt LL well defined round or oval lesion Confirmed by aortography and venous drainage is via
pulmonary vein or bronchial vein
Bronchogenic cyst well defined, round or oval in shaped ,smooth wall 2/3rd are intrapulmonary , located medial 1/3rd of LL Peak incidence in 2nd and 3rd decade of life
CT SCAN
standard CT examination without contrast material enhancement may be performed
Ensure there are no other findings, such as additional nodules lymphadenopathy, pleural effusion, chest wall involvement, or adrenal mass.
concerns about radiation dose to the patient, subsequent follow-up CT may be limited to the nodule location.
CT CON… Thin-section CT scans obtained through the nodule
provide information regarding nodule size (by using diameters from the largest cross-sectional area or volume measurement) attenuation, edge characteristics, and the presence of calcification,cavitation, or fat .
Sequential thin-section CT (1 3-mm section width) performed through the entire nodule with a single breath hold and without contrast
GROWTH RATE ASSESMENT Absence of detectable growth over a 2-year period of
is a reliable criterion for establishing that a pulmonary nodule is benign
Difficult to detect growth in small (< 1cm) nodules. To overcome this limitation,
growth rate of small nodules be assessed using serial volume measurements rather than diameter
Computer-aided 3D quantitative volume measurement methods have been developed and applied clinically
All these volumetric methods are focused on solid pulmonary nodule
DOUBLING TIME
Volume is doubled if diameter has increased by at least 1.25 times in at least 2 dimension
Usally malignant lesions have a doubling time of 1-6 months.
Masses are considered benign when they have not change in size for 18 months
many lesions are not completely spherical Hemorrhage into a lesion can increase the volume
dramatically bronchial carcinoids and BAC long doubling times
DYNAMIC –HELICAL CT The lesion should be at least 10mm
Contrast enhancement is directly related to the
vascularity and blood flow
Nodule examined 3mm collimation before and after
administration of contrast
1min interval up to 4min after administration of contrast
Nodule enhancement= peak mean – base line
attenuation
CON… Early cut of point for differention of benign from
malignant nodule - 15H enhancement
Early study more focus on early phase of dynamic
CT .this studies are more sensitive but less specific
Overlap was found between malignant and benign
nodules for example, active granulomas and benign
vascular tumours
CON… FALSE POSITIVE: active infection active inflammation FALSE NEGATIVE Broncho alveolar ca Lesion with central necrosis cavitatory lesion
MRI Special circumstances – contrast allergy etc
Not routinely used due to cost factor
CT is as good
TISSUE DIAGNOSIS
TTNA-TRANS THORACIC NEEDLE
ASPIRATION
24 G needle
CORE BIOPSY
BRONCHOSCOPIC BIOPSY
TRANS THORACIC NEEDLE BIOPSY (TTNB) indication
FNAB can be used to diagnose malignancy and determine the histologic type of malignancy. In patients who are candidates for surgery
FNAB may be used to diagnose benign disease, thus obviating surgery
Contraindications inability of the patient to cooperate Other relative contraindications bleeding diathesis, previous pneumonectomy, severe emphysema, severe hypoxemia, pulmonary artery hypertension, nodules which successful biopsy cannot be performed
TTNB...
Nodules that are in the lower lobes or adjacent to the
heart may be difficult to access because of varying
breath holds and diaphragmatic and cardiac motion
TTNB... When the FNAB sample is interpreted as malignant or
specific benign condition is, further workup based on
diagnosis.
when a nonspecific benign condition is diagnosed,
further evaluation is required
The most common complications of
FNAB are pneumothorax and hemorrhage
PET with FDG-F18
PET-CT may be selectively performed to characterize SPNs when dynamic helical CT shows inconsistent results between morphological and , hemodynamic characteristics
PET 18F-FDG is accurate ,noninvasive diagnostic test PET-CT provide more anatomical detail than PET alone
or CT alone Increased uptake of 18F-FDG –MALIGNANT Decreased uptake - BENIGN False positive- infection /inflammation False negative –BAC, carcinoid Best test for lesion >1cm lesion
SPN IN RT LOWER LOBE IN CT, SHOWING INCREASED UPTAKE ON PET- ADENOCARCINOMA
CLINICAL BENIGN MALIGNANTAge < 35 yrs >35 yrsh/o smoking - +
Exposure to TB
+ -
Exposure to carcinogens
- +
Primary lesion elsewhere
- +
Chest X ray BENIGN MALIGNANT
size < 3cm >3 cmlocation Not specific Upper lobesmargins smooth Spiculatedcalcification Central,
diffuse, laminated, popcorn
Eccentric/ stippled
Growth pattern Stable for 2 yrs Presence of growth
Satellite nodule more less
CT BENIGN MALIGNANT
Fat + -
Bubble like lucencies
uncommon Common
Enhancement < 25 HU > 25HU
densitometry > 200 HU < 200 HU
DIAGNOSTIC CRITERIAINDICATED A MALIGNANT NODULE
≥ 25 H wash-in and 5–31 H washout
lobulated margin
spiculated margin
absence of a satellite nodule
SUMMARY OF RECOMMENDATIONS FOR FOLLOW-UP ANDMANAGEMENT OF INCIDENTAL SMALL (< 8MM) NODULES DETECTED ON NON-SCREENING CT SCANS
NODULE SIZE IN MM
LOW RISK PATIENT HIGH RISK PATIENTT
<4MM NO FOLLOWUP NEEDED IN ITIAL CT AT 12 MONTH, IF UNCHANGED, NO FOLLOWUP
4-6MM IN ITIAL CT AT 12 MONTH, IF UNCHANGED, NO FOLLOWUP
INITIAL CT AT 6TO12 MONTH THEN AT 18 -24 MON IF NO CHANGE
6-8 MM INITIAL CT AT 6TO12 MONTH THEN AT 18 -24 MON IF NO CHANGE
INITIAL CT AT 3 TO 6 MONTH THEN AT 9 TO 12 MON AND 24MON IF NO CHANGE
>8MM CT FOLLOWUP 3, 9, 24 MON/DYNAMICCT/PET CT/BIOPSY
CT FOLLOWUP 3, 9, 24 MON/DYNAMICCT/PET CT/BIOPSY
MacMahon, H. et al. Guidelines for management of small pulmonary nodules detected on CT scans:A statement from the Fleischner Society. Radiology 2005; 237: 395-400
DO not use in pts <35y/o; h/o malignancy or in pts w fever.
CONCLUSION CT screening, has increased the detection rate of small nodular
lesions,
In providing information about morphological and hemodynamic
characteristics with high specificity and reasonably high accuracy,
CT scan can be used for the initial assessment of SPNs.
PET-CT is more sensitive for detecting malignancy than dynamic
helical CT, and all malignant nodules may be potentially diagnosed
as malignant by these two techniques.
PET-CT may be selectively performed to
characterize SPNs when dynamic helical CT shows
inconsistent results between morphological and
hemodynamic characteristics
Serial volume measurements are currently the most
reliable methods for the tissue characterization of
subcentimeteric nodule
THANK YOU
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