Solitary lytic lesions

Solitary Lytic Lesions

Dr. Y .Madhu Madhava Reddy


• Lucent bone lesion in the medulla -well-defined, marginal sclerosis, no expansion

• Lucent Bone Lesion In The Medulla -Well-defined, No Marginal Sclerosis, No Expansion

• Lucent bone lesion in the medulla -ill-defined • Lucent bone lesion in the medulla -well-defined,

eccentric expansion • Lucent bone lesion - grossly expansile • Subarticular lucent bone lesion

Lucent bone lesion in the medulla -well-defined, marginal sclerosis, no expansion

• 1. Geode • 2. Healing benign or malignant bone lesion — e.g. metastasis,

eosinophilic granuloma or brown tumour. • 3. Brodie's abscess. • 4. Benign bone neoplasms • (a) Simple bone cyst* — 75% arise in the proximal humerus and femur. • (b) Enchondroma* — more than 50% are found in the tubular bones of

the hands. ± Internal calcification. • (c) Chondroblastoma* — in an epiphysis. Most common sites are

proximal humerus, distal femur and proximal tibia. Internal hazy calcification.

• 5. Fibrous dysplasia*.

Lucent bone lesion in the medulla -well-defined, no marginal sclerosis, no expansion

• 1. Metastasis — especially from breast, bronchus, kidney or thyroid.

• 2. Multiple myeloma*. • 3. Eosinophilic granuloma*. • 4. Brown tumour of hyperparathyroidism*. • 5. Benign bone neoplasms • (a) Enchondroma*. • (b) Chondroblastoma*.

Lucent bone lesion in the medulla -ill-defined

• 1. Metastasis. • 2. Multiple myeloma*. • 3. Osteomyelitis. • 4. Lymphoma of bone. • 5. Long bone sarcomas • (a) Osteosarcoma*. • (b) Ewing's sarcoma*. • (c) Central chondrosarcoma*. • (d) Fibrosarcoma and malignant fibrous histiocytoma.

Lucent bone lesion in the medulla -well-defined, eccentric expansion

• 1.Giant cell tumour* — typically subarticular after epiphyseal fusion (3% are metaphyseal prior to fusion). Ill-defined endosteal margins. Septa. ± Soft-tissue extension and destroyed cortex. Mostly long bones.

• 2. Aneurysmal bone cyst* — in the unfused metaphysis or metaphysis and epiphysis following fusion of the growth plate. Intact but thin cortex. Well-defined endosteal margin. ± thin internal strands of bone. Fluid-fluid levels on CT and MRI.

Lucent bone lesion in the medulla -well-defined, eccentric expansion

• 3. Enchondroma* — diaphyseal. Over 50% occur in the tubular bones of the hands and feet. Internal ground glass appearance ± calcification within it. May be multilocular in long bones.

• 4. Non-ossifying fibroma (fibrous cortical defect)* — frequently in the distal tibia or femur and produces an eccentric expanded cortex. (In a thin bone such as the fibula central expansion is observed.) Metaphyseal. Smooth, sharp margins with a thin rim of surrounding sclerosis.

• 5. Chondromyxoid fibroma* — 75% in the lower limbs (50% in the proximal tibia). Metaphyseal and may extend into the epiphysis. Frequently has marginal sclerosis.

Lucent bone lesion - grossly expansile

• MALIGNANT BONE NEOPLASMS • 1. Metastases — renal cell carcinoma and thyroid; less

commonly melanoma, bronchus, breast and phaeochromocytoma.

• 2. Plasmacytoma* — ± soft tissue extension. ± Internal septa. • 3. Central chondrosarcoma/lymphoma of bone/

fibrosarcoma — when slow growing may have this appearance.

• 4. Telangiectatic osteosarcoma* — rare. Uncommon vascular variant that mimics aneurysmal bone cyst.


• BENIGN BONE NEOPLASMS • 1. Aneurysmal bone cyst*• 2. Giant cell tumour*• 3. Enchondroma* — ground-glass

appearance ± internal calcifications.


• NONNEOPLASTIC • 1. Fibrous dysplasia* — ground-glass appearance ± internal

calcification. Modelling deformities of affected bone. • 2. Haemophilic pseudotumour— especially in the iliac wing

and lower limb bones. Soft-tissue swelling. ± Haemophilic arthropathy.

• 3. Brown tumour of hyperparathyroidism* — the solitary skeletal sign of hyperparathyroidism in 3% of patients. Most commonly in the mandible, followed by pelvis, ribs and femora. Usually unilocular.

• 4. Hydatid.

Subarticular lucent bone lesion • Arthritides• Osteoarthritis — may be multiple 'cysts' in the load-bearing areas of

multiple joints. Surrounding sclerotic margin. Joint-space narrowing, subchondral sclerosis and osteophytes.

• Rheumatoid arthritis* — no sclerotic margin. Begins periarticularly near the insertion of the joint capsule. Joint-space narrowing and juxta-articular osteoporosis.

• Calcium pyrophosphate arthropathy— similar to osteoarthritis but frequently larger and with more collapse and fragmentation of the articular surface.

• Gout — ± erosions with overhanging edges and adjacent soft-tissue masses.

• Haemophilia*.

Subarticular lucent bone lesion • NEOPLASTIC • Metastases/multiple myeloma* — single or multiple. Variable

appearance. • Aneurysmal bone cyst* — solitary. Expansile. Narrow zone of

transition. • Giant cell tumour* — solitary. Eccentric. Ill-defined endosteal margin. • Chondroblastoma* — solitary. Predilection for the proximal ends of

the humerus, femur and tibia. Contains amorphous or spotty calcification in 50%.

• Pigmented villonodular synovitis* — mainly the lower limb, especially the knee. Soft-tissue mass. Cyst-like defects with sharp sclerotic margins. May progress to joint destruction.


Solitary lytic Lesions

• These lesions are sometimes referred to as benign cystic lesions, which is a misnomer since most of them are not cystic, except for SBC and ABC.

• It is true that in patients under 30 years a well-defined border means that we are dealing with a benign lesion, but in patients over 40 years metastases and multiple myeloma have to be included in the differential diagnosis.

Solitary lytic Lesions• Notice the following:• In patients In patients > 40 years metastases and

multiple myeloma are by far the most common well-defined osteolytic bone tumors.

• Patients with Brown tumor in hyperparathyroidism should have other signs of HPT or be on dialysis.

• Differentiation between a benign enchondroma and a low grade chondrosarcoma can be impossible based on imaging findings only.

• Infection is seen in all ages.

Fibrous dysplasia• Fibrous dysplasia is a benign disorder characterized by tumor-like

proliferation of fibro-osseus tissue and can look like anything.FD most commonly presents as a long lesion in a long bone.FD is often purely lytic and takes on ground-glass look as the matrix calcifies.In many cases there is bone expansion and bone deformity.The ipsilateral proximal femur is invariably affected when the pelvis is involved.When FD in the tibia is considered, adamantinoma should be in the differential diagnosis.

• Discriminator:• If periosteal reaction or pain is present, exclude fibrous dysplasia,

unless there is a fracture.

Fibrous dysplasia

• Differential diagnosis:– In young patients with location in proximal

humerus or femur: solitary bone cyst or aneurysmal bone cyst.

– In eccentric locations: NOF or adamantinoma (tibia).

– When calcifications are present: chondroid lesion (enchondroma).

Fibrous dysplasia

Fibrous dysplasia

FD

Enchondroma• Enchondroma is a benign cartilage tumor. • Frequently it is a coincidental finding.

• In the phalanges of the hand it frequently presents with a fracture. It is the most common lesion in the phalanges, i.e. a well-defined lytic lesion in the hand is almost always an enchondroma. In some locations it can be difficult to differentiate between enchondroma and bone infarct.

• It is almost impossible to differentiate between enchondroma and low grade chondrosarcoma based on radiographic features alone. Ollier's disease is multiple enchondromas. Maffucci's syndrome is multiple enchondromas with soft tissue hemangiomas.

Enchondroma• Features that favor the diagnosis of a low-grade

chondrosarcoma:• Higher age• Size > 5 cm• Activity on bone scan• Fast enhancement on dynamic contrast enhanced MR series• Endosteal scalloping of the cortical bone•

Discriminators :• Must have calcification except in phalanges.• No periostitis.

Enchondroma

Enchondroma

Enchondroma

Eosinophilic granuloma

• EG is a non-neoplastic proliferation of histiocytes and is also known as Langerhans cell histiocytosis.

• It should be included in the differential diagnosis of any sclerotic or osteolytic lesion, either well-defined or ill-defined, in patients under the age of 30.

• The diagnosis EG can be excluded in age > 30.EG is usually monostotic, but can be polyostotic.

Eosinophilic granuloma

Eosinophilic granulomaleftOsteolytic lesion arising from the neurocranium with associated soft tissue swelling.middleMixed lytic-sclerotic lesion, not well-defined with solid periosteal reaction.rightSharply defined osteolytic lesion of the skull. There is no 'button sequestrum', which is more or less pathognomonic.

Discriminator:Must be under age 30

Giant cell tumor• GCT is a lesion with multinucleated giant cells.

In most cases it is a benign lesion.• Malignant GCT is rare and differentiation between benign or malignant

GCT is not possible based on the radiographs.• GCT is also included in the differential diagnosis of an ill-defined

osteolytic lesion, provided the age and the site of the lesion are compatible.

•Discriminators:

• Epiphyses must be closed.• Must be an epiphyseal lesion and abut the articular surface.• Must be well-defined and non-sclerotic margin.• Must be eccentric.

Giant cell tumor• Presents as an eccentric lytic lesion with a geographic pattern of bone

destruction, but can also have a more aggressive appearance with ill-defined borders.

• By far most giant cell tumors are seen around the knee. GCT is located in the epiphysis with or without extension to metaphysis and frequently abuts the articular surface.

• Most common bone tumor in adults aged 25 - 40 y.• Differential diagnosis:

– ABC may have the same radiographic features but is found in a younger age group.

– Chondroblastoma is also located in the epiphysis, but is seen exclusively in the epiphysis without extention to the metaphysis and is seen in a younger age group.

– Metastases, especially in older patients.

Giant cell tumor

GCT

Non Ossifying Fibroma• NOF is a benign well-defined, solitary lesion due to proliferation of

fibrous tissue. It is the most common bone lesion. • NOF is frequently a coincidental finding with or without a fracture.

NOF usually has a sclerotic border and can be expansile.• They regress spontaneously with gradual fill in.

NOF may occur as a multifocal lesion. • The radiographic appearance is almost always typical, and as such

additional imaging and biopsy is not warranted.

Discriminators:• Must be under age 30.• No periostitis or pain.

NOF

• Typical presentation as an eccentric, multi-loculated subcortical lesion with a central lucency and a scalloped sclerotic margin

Osteoblastoma

• Osteoblastoma is a rare solitary, benign tumor that produces osteoid and bone.Consider osteoblastoma when ABC is in the differential diagnosis of a spine lesion.A typical osteoblastoma is larger than 2 cm, otherwise it completely resembles osteoid osteoma.

•Discriminator:

• Mention when ABC is mentioned.

Osteoblastoma

• Calcification or ossification of osteoid tissue within the tumour may cause a PUNCTATE or AMORPHOUS increase in density best seen on CT.

Metastases

• Metastases are the most common malignant bone tumors.

• Metastases must be included in the differential diagnosis of any bone lesion, whether well-defined or ill-defined osteolytic or sclerotic in age > 40.

• Bone metastases have a predilection for hematopoietic marrow sites: spine, pelvis, ribs, cranium and proximal long bones: femur, humerus.

Metastases

• Metastases can be included in the differential diagnosis if a younger patient is known to have a malignancy, like neuroblastoma, rhabdomyosarcoma, retinoblastoma.Most common osteolytic metastases: kidney, lung, colon and melanoma.Most common osteosclerotic metastases: prostate and breast.

• Discriminator:• Must be over age 40.

Multiple Myeloma• It must be included in the differential diagnosis of any lytic bone lesion,

whether well-defined or ill-defined in age > 40.• The most common location is in the axial skeleton (spine, skull, pelvis and

ribs) and in the diaphysis of long bones (femur and humerus).• Most common presentation: multiple lytic 'punched out' lesions. • Multiple myeloma doe not show any uptake on bone scan.

Discriminator:• Must be over age 40. Differential diagnosis:• multiple lesions: metastases.• solitary lesion: chondrotumor, GCT and lymphoma.

Multiple Myeloma

Multiple Myeloma

Aneurysmal Bone Cyst• ABC is a solitary expansile well-defined osteolytic bone lesion, that

is filled with blood. It is named aneurysmal because it is expansile.

• ABC is thought to be the result of a reactive process secondary to trauma or increased venous pressure. Sometimes an underlying lesion like GCT, osteoblastoma or chondroblastoma can be found.

• ABC can occur almost anywhere in the skeleton.

Discriminators:• Must be under age 30.• Must be expansile

ABC• Radiographic hallmark is multicystic eccentric expansion

(blow-out) of the bone,with thinned out cortex and a buttress or thin shell of periosteal response.

• Well defined endosteal margin.• Fluid-fluid levels on CT/MRI(represent sedimentation of red blood cells and serum within cystic cavities). Peripheral enhancement on contrast studies.

ABC

ABC

Solitary Bone Cyst• Solitary bone cyst, also known as unicameral bone cyst, is a true cyst. • SBC frequently presents with a fracture.

Sometimes a fallen fragment is appreciated. Predilection sites: proximal humerus and femur.

• Usually less expansion compared with ABC. Differential diagnosis: ABC, FD when cystic. SBC may migrate from metaphysis to diaphysis during growth of the bone.

Discriminators:• Must be under age 30.• Must be centric

SBC

Brown tumours • One of the manifestations of hyperparathyroidism.• Well-defined, purely lytic lesions , cortex may be thinned

and expanded, usually hypervascular.• Brown tumors can occur in any bone and present as

osteolytic lesions with sharp margins. Septa and ridges may be seen.

• Differential diagnosis: ABC, metastases and GCT depending on location and age.

• Discriminators:• Must have other signs of HPT.

Infection• Infection or osteomyelitis is the great mimicker of bone tumors. • It has a broad spectrum of radiographic features and occurs at

any age and has no typical location. In the chronic stage it can mimic a benign bone tumor (Brodies abscess).

• In the acute stage it can mimic a malignant bone tumor with ill-defined margins, cortical destruction and an aggressive type of periostitis.

• Only when there is a thick solid periosteal reaction we can recognize the non-malignant underlying process.

Infection

Brodie Abscess• It refers to an abscess related to focus of chronic osteomyelitis in a

bone. • Plain film findings:• Lytic lesion often in an oval configuration that is oriented along the

long axis of the bone• surrounded by thick dense rim of reactive sclerosis that fades

imperceptibly into surrounding bone• lucent tortuous channel extending toward growth plate prior to

physeal closure (pathognomonic)• periosteal new-bone formation• +/- adjacent soft-tissue swelling• may persist for many months

Brodie Abscess

Chondroblastoma• Epiphysis of long bones or apophysis• Immature skeleton ,Second decade, M>F• epiphyses of long bones such as the humerus, tibia

and femur • Well defined radiolucent oval lesion with thin rim of

sclerosis• Cortical expansion• Stippled calcification upto 50 % of cases• Well defined endosteal margins• Very rare malignant transformation

Chondroblastoma• The patella, carpal and tarsal bones can be regarded as epiphysis

conceirning the differential diagnosis. On the left a chondroblastoma located in the patella.

• Discriminators :• must be under age 30.• must be in the epiphysis.

D/D• GCT -older age group (closed physis)• clear cell chondrosarcoma - old age, large mass, absent bone edema• osteomyelitis with abscess (e.g. Brodie abscess) • intraosseous ganglion

Chondroblastoma

Chondroblastoma

Chondromyxoid fibroma

• Meta-diaphyseal• Preferential sites -proximal tibia, femur, foot• Eccentric-medulla• Lobulated contour• Matrix mineralisation unusual• Second /third decade

Chondromyxoid fibroma

Intraosseous ganglion• An intraosseous ganglion is a benign subchondral

radiolucent lesion without degenerative arthritis. • Tends to occur in middle age with localised pain.• They are uni-/multilocular cysts surrounded by a

fibrous lining, containing gelatinous material.• They occur due to mucoid degeneration of intraosseous

connective tissue perhaps due to trauma/ischemia or• Due to penetration of juxtaosseous soft-tissue ganglion

(=synovial herniation) into underlying bone (occasionally).

Intraosseous ganglion

Desmoplastic fibroma

• These extremely rare bone tumours that do not metastasize, but may be locally aggressive. They are considered to be a bony counterpart of soft tissue desmoid tumours and are histologically identical.

• Incidence is approximately 0.3%. The most common areas of involvement include the mandible, pelvis and femur .

• Mean age at presentation is 21, and there is no sex predilection.


• Typically seen as a lytic bone lesions with a geographic pattern of bone destruction

• often has a narrow zone of transition and non-sclerotic margins

• internal pseudotrabeculation: > 90%.• no matrix mineralisation• widening of the host bone from gradual

apposition of periosteal new bone formation: ~ 90%.



• Desmoplastic fibromas histologically are identical to soft tissue desmoid tumors, with abundant collagenous stroma and little cellularity or pleomorphism. The main cell types that are seen include: fibroblasts, myofibroblasts, and undifferentiated mesenchymal cells

Arachnoid granulation

• Aka Pacchionian granulation most frequently occurs in a parasagittal location and can cause an osteolytic, sharply circumscribed lucency on a skull x-rays, or a filling defect in dural venous sinuses, which can be mistaken for dural venous thrombosis. They increase in size with age and are seen in approximately two-thirds of patients.



Geode

• Aka Sub chondral cyst. It is a well-defined lytic lesion in the periarticular surfaces. A geode is one of the common differential diagnoses of an epiphyseal lesions (lytic).

• Presumably, one method of geode formation takes place when synovial fluid is forced into the subchondral bone, causing a cystic collection of joint fluid. Another aetiology is following a bone contusion, in which the contused bone forms a cyst.

Geode

• Associations• degenerative joint disease (DJD)• rheumatoid arthritis• calcium pyrophosphate dihydrate crystal

deposition disease (CPPD)• avascular necrosis

Geode

Hydatid of Bone

• Rare manifestation of Echinococcosis.• It is important to consider the possibility of Hydatid

disease of the bone as a differential diagnosis of lucent lesions of the bone especially in the areas where it is prevalent.

• It is most commonly seen in the spine and pelvis, followed by the femur, tibia, humerus, skull, and ribs.

• Osseous foci may be manifested as pain and deformity.

Hydatid of Bone

Hydatid of Bone

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Solitary lytic lesions