Author: Micah Cohen
Darren Fitzpatrick
Radiograph CT MRI - T1 MRI - T2 or STIR MRI - Post-contrast T1 Radionuclide Gross Pathology Histology Additional comments
Fibrous dysplasia Ground glass, lucent or sclerotic matrix. Lesion within marrow, can be eccentric with sclerotic rim.

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Axial bone window of the pelvis showing femoral lesion with expansion of medullary cavity and ground glass matrix.

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Coronal T1W image showing mildly heterogenous signal intensity, isointense to muscle Coronal T2W image showing heterogeneous slightly hyperintense and hyperintense slightly expansile lesion within left femur Pre-contrast: Lesion demosntrates mild heterogeneous and/or solid enhancement on post-contrast imaging

Post-contrast: Lesion demosntrates mild heterogeneous and/or solid enhancement on post-contrast imaging
Mildly increased radionuclide uptake in fibrous dysplasia on technetium-99m methylene diphosphonate scan Fibrous dysplasia of proximal femur with classic shepherd's crook deformity. Arrows are pointing to multiple dysplastic fibrocartilaginous islands within expanded marrow cavity Myxofibrous tissue containing woven bony trabeculae Mazabraud xray. Majority of patients <30 years old. Mono and polyostotic forms. Associations with McCune Albright, Mazabraud, hyperthyroidism, hyperparathyroidism, acromegaly, diabetes mellitus, and Cushing's. Mazabraud syndrome is polyostotic fibrous dysplasia with intramuscular myxomas. Myxomas demonstrate iso-intense/low T1 and hyperinterintese T2 or STIR signal with minimal rim or no enhancement. McCune Albright is multi-focal, polyostotic fibrous dysplasia which usually involves the skull and is associated with precocious puberty.

Mazabraud T1

Mazabraud T2

Mazabraud post-contrast T1

Mazabraud Bone scan

McCune Albright skull

McCune Albright ribs
Adamantinoma Elongated, multilocular lytic lesion with narrow zone of transition within the tibial marrow cavity with associated endosteal scalloping and cortical expansion. No periosteal reaction or violation of the cortex. Lesions very frequently involve the tibia and can simultaneously involve the fibula. Lesions can sometimes be centered in the anterior tibial cortex. Another example of an adamantinoma as a lucent lesion centered within the anterior tibial cortex. Adamantinoma manifest as an iso-intense T1 marrow signaled lesion Another example of an adamantinoma as a hyperintense STIR signal lesion centered within the anterior tibial cortex. Intense, nearly homogeneous, post contrast enhancement. Elongated, increased focal uptake on Tc-99m MDP scans. Lesion fills the medullary canal with expansion of the cortex and endosteal scalloping. Neoplastic epithelial cells surrounded by osteofibrous stroma. Rare low grade malignant lesion (<.5% of malignant bone lesions) of the tibia/fibula seen predominantly in 10-20 year olds. Longitudinal mixed lucent and sclerotic lesions in "soap bubble" pattern. Periosteal reaction in only ~15%. Narrow zone of transition. Synchronous lesions in fibula seen in 5-10%. Similar to osteofibrous dysplasia. Associated with extra copies of chromosomes 7,8,12,19, or 21.
Eosinophilic Granuloma Radiographic findings depend on stage of disease. Early lesions are lytic, ill-defined margins, periosteal reaction. Later lesions can be well defined with sclerotic rim and expansion/remodeling. Lytic lesions may contain a sequestrum. Skull lesions have "beveled" appearance with asymmetric involvement of tables of calvarium. Multiple lesions can coalesce to form a "geographic skull."

Eosinophilic Granuloma in skull with sequestrum

Vertebra Plana
Manifest as a lytic, marrow lesion with ill-defined margins with possible periosteal reaction. Helpful in defining extent of osseous destruction and involvement of soft tissue.

Sequestrum can occur
Hypointense marrow replacing lesion Hyperintense bone marrow replacing mass Variable lesional enhancement on postgadolinium Imaging. Increased uptake on Technetium-99m-MDP bone scans. ~65% sensitivity Proliferation of Langerhans histiocytes form granulomas with surrounding eosinophils and other inflammatory cells. "Birbeck" granules seen within the pathologic Langerhans cells. Typically pts <30. Predominantly involves flat bones including skull, ribs, pelvis. Long bones involved ~30% of time.
Enchondroma 1) Ring and arc matrix appearance in proximal humerus enchondroma with associated shallow endosteal scalloping.


2) Enchondroma radiograph (from Mount Sinai)


Axial section through distal femoral enchondroma revealing chondroid matrix and shallow endosteal scalloping. CT can be helpful is discerning nature of chondroid matrix that is unclear or indeterminate on radiographs. Lobulated lesion with heterogeneous and predominantly intermediate signal with low signal areas representing mineralization Lobulated lesion with heterogeneous, predominantly high signal intensity (hyaline cartilage) with foci of hypointensity representing mineralization. Septal, nodular, and peripheral enhancement in lesion in proximal humerus. Enhancement pattern not useful in distinguishing from chondrosarcoma. Low grade uptake on Tc-99m MDP, less than the physiologic uptake seen in anterior iliac crest, as compared to chondrosarcomas which tend to display uptake greater than that seen at the anterior iliac crest. 1)Grayish lesions of the hand viewed at surgery.
2) Lobulated lesion in proximal humeral metaphysis (black asterisk) with surrounding regions of normal fatty marrow (white asterisks).
Partly hyaline cartilaginous matrix, partly myxoid matrix bordering on preexisting bone. Well defined lytic lesions commonly found in hands and feet, metadiaphyses of long bones. Associated w/calcification in lesions outside of the hands and feet.
Mafucci syndrome: Enchondromas of the hands and feet manifest as well defined lytic osseous lesions without chondroid matrix. Often discussed in the context of multiple encondromatoses such as Mafucci syndrome (in association with soft tissue hemangiomas) and Ollier's disease. Maffuci sydrome with a reported higher rate of malignant transformation to chondrosarcoma than Ollier's. Enchondromas in the axial skeleton (not involving hands and feet) can be difficult to distinguish from low grade intramedullary chondrosarcomas. Enchondromas observed to exhibit a lesser depth of endosteal scalloping than low grade chondrosarcomas. Also, chondrosarcoma more commonly associated with cortical destruction, cortical remodeling, cortical thickening, pathologic fracture, and soft tissue extension than enchondroma. Suspicion for chondrosarcoma should be raised if the lesion increases in size and produces pain.
Ollier's disease: Multiple encondromatoses.  
Giant Cell Tumor AP and lateral radiographs of the knee demosntrate an eccentrically located, lucent lesion in the distal femoral epiphysis of a skeletally mature patient with a narrow zone of transition and a nonsclerotic rim. Can display multiloculated appearance from prominent trabeculation.

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Axial CT of a giant cell tumor demosntrates extensive, expansile remodeling of bone with no internal mineralization in a distal femoral epiphyseal lesion. Intermediate signal mass replacing marrow in distal femoral epiphysis with soft tissue extension. Lobulated, heterogeneous, intermediate T2 signal characteristics of giant cell tumor may be related to hemosiderin and or increased cellularity or high collagen content. Multi-lobulated foci of increased T2 signal in this lesion may be related to secondary aneurysmal bone cyst formation. Pre-contrast: Solid enhancing hypervascular elements of GCT with peripherally enhancing elements around secondarily formed ABC.

Post-contrast: Solid enhancing hypervascular elements of GCT with peripherally enhancing elements around secondarily formed ABC.
May display peripheral increased radiotracer uptake. Can see central photopenia-"donut sign" Subchondral mass at distal femoral epiphysis with hemorrhagic regions inferiorly and anterior extension into soft tissue. Large number of osteoclast Giant cells in a background of mononuclear cells. Accounts for 18-23% on benign bone neoplasms. No internal mineralization. Must meet four criteria: 1) closed epiphyses 2) meta-epiphyseal lesion that abuts the articular surface 3) eccentrically located 4) narrow zone of transition with nonscelrotic rim (though can have sclerotic rim in flat bones). Tumors are hypervascular and can see foci of hemorrhage in some modalities. Periosteal reaction is uncommon. Most common lesion associated with secondary aneurysmal bone cyst formation.
Nonossifying fibroma Smoothly marginated, cortically based, lucent lesion of distal femoral metaphysis or diaphysis with sclerotic rim and no periosteal reaction. Lesion can appear lucent early on and sclerotic during "burnt out phase"

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Findings on CT mimic the radiographic findings. This is an atypically large non-ossifying fibroma centered on the cortex of the anterior femoral diaphysis.

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Cortically based, intermediate intensity lesion surrounded by low intensity sclerosis. Low intensity sclerosis surrounding variable intensity, cortically based lesion determined by relative amounts of fibrous tissue, collagen, foamy histiocytes, sclerosis. More often hypointense than hyperintense. Often displays avid enhancement. Shows mild enhancement in this image. Increased uptake on technetium-99m-MDP bone scans. Also displays FDG-PET avidity, but with lower SUV than malignant lesions. Also known as fibroxanthoma or fibrous cortical defect when less than 3cm. Most common benign fibrous tumor of bone. Seen most commonly in skeletally immature patients in metaphyses of long bones. Cortically based lesions with thin rim of sclerosis, scalloped borders, and no periosteal reaction. Natural course is involution with progressive sclerosis.
Osteoblastoma There are 3 classic radiographic patterns of osteoblastoma: 1) central lucency with peripheral sclerosis 2) calcified expansile lesion with sclerotic rim. 3) aggressive lesion with osseous expansion, bone destruction, extension into soft tissues, with variable internal matrix calcification. Here we see a lucent lesion with central sclerosis

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CT of same lesion - more accurately displays well defined lucent lesion with osteoid central nidus.

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Expansile type osteoblastoma: low to intermediate signal on T1 weighted images. Intermediate to high signal with edema surrounding the peripheral hypointensity rim of sclerosis. Central low signal intensity represents the osteoid matrix. Can demonstrate variable degrees of enhancement with solid central or mild peripheral enhancement. Focal increased radiotracer uptake on bone scan. Expansile, lobulated mass with whitish tissue representing osseous matrix. Interconnecting trabecular bone and fibrovascular stroma - less organized than with steoid osteoma. Histologically similar to osteoid osteoma but with differing clinical presentation of dull localized pain. Majority occur in young adults in 2nd-3rd decade with 30-40% occurring in spine with equal distibution in cervical, thoracic and lumbar regions. Commonly involves the posterior elements, sometimes extending into vertebral body. Typically greater than 1.5-2.0 cm in size (as opposed to osteoid osteoma which tends to be less than 2.0 cm). Lesions may display central lucency/nidus greater than 1.5cm (osteoid osteoma nidus tends to be less than 1.5cm). Aneurysmal Bone Cyst component can be seen in 10-15%.
Aneurysmal Bone Cyst Four radiographic stages of aneurysmal bone cyst: 1) Initial phase- well defined lytic lesion. 2) Growth phase- purely lytic lesion with ill-defined margins. 3) Stabilization- "soap bubble" appearance from development of osseous shell. 4) Healing. Well-defined lytic lesion with internal septations and cortical breakthrough. Well-defined lesion with internal septation and may display fluid-fluid levels. Foci of hyperintensity from blood products. Low signal rim from intact, thickened periosteal rim. Multiloculated cystic structure with fluid-fluid levels with heterogeneous intensity from evolving blood products with predominantly areas of hyperintensity. Low intensity rim from intact and thickened periosteal rim. Smooth, peripheral and internal septation enhancement. Enhancement of other solid components may indicate association with a preexisting lesion. Moderate to intense peripheral uptake with central photopenia-"donut sign" (~64% of cases-but not specific as seen in GCT, telangiectatic osteosarcoma, and chondrosarcoma). Lesion with multiple blood-filled spaces. Blood filled cystic spaces separated by spindle cell stroma containing osteoclast-like giant cells and osteoid. Mineralized chondroid-like matrix found in one third of cases. Rare benign bone lesion (1.4-2.3% of primary bone tumors) predominantly in 5-20 year old patients. Spinal involvement in 3-20%. Usually involves the posterior elements with extension into adjacent vertebra, disks, ribs, and soft tissue. May be the result of traumatic subperiosteal hemmorhage, osseous vascular disturbance, or bleeding into a preexisting lesion (29-35%). Most common preexisting lesion associated with is giant cell tumor. Also, commonly seen with osteoblastoma, chondroblastoma, and angioma.
Solitary/Unicameral Bone Cyst Lucent, expansile lesion in distal femoral metadiaphysis with associated "fallen fragment" sign indicating pathologic fracture and pathognomonic for simple bone cyst. Axial section through distal femoral metaphysis displaying expansile lucent lesion with mixed cystic and soft tissue elements. T1 weighted images display mixed fat and cystic elements with iso-intense T1 signal intensity Bright T2 signal with daughter cysts in a proximal humerus metadiaphyseal lesion Bright T2 signal with daughter cysts in a proximal humerus metadiaphyseal lesion Lucent, fluid filled lesion usually seen in metaphyses of long bones in teenage males. Also seen in pelvis and axial skeleton. Associated with "fallen fragment" sign (bone fragment within cyst) associated with pathologic fractures.
Hyperparathyroidism/Brown's Tumor Well-defined lucent lesions which may be cortical or eccentrically located in marrow. May be expansile with endosteal scalloping. Common sites include, ribs,pelvis, facial bones, and femurs. Look for other associated signs of hyperparathyroidism (see "additional commentsl" cell)

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Well-defined lucent, expansile lesion. Healing lesions may appear sclerotic.

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Lesions are bright and well defined on T2 weighted images. Notice the dark marrow signal in this patient with renal osteodystrophy. Seen in the setting of hyperparathyroidism-more commonly with primary than with secondary. Elevated PTH causes increased osteoclast replacement of bone with fibrovascular tissue causing lytic lesions. Usually accompanied by other signs of hyperparathyroidism including subperiosteal bone resorption and periosteal reaction.
Chondroblastoma Eccentric, well-defined lucent lesion in epiphysis/apophysis with sclerotic margin. Vast majority occur in long bones and are eccentrically positioned within eiphyseal/apophyseal location with some occurring in metaphyses. This image demonstrates an eccentrically positioned, well-defined lytic lesion with a sclerotic rim within the patella. Eccentric, well-defined lytic lesion in epiphysis/apophysis with sclerotic margin. Axial CT image through left distal lateral femoral condyle shows a well-defined eccentrically located lucent and expansile epiphyseal lesion. Peripheral rim of low intensity surrounding lesion with adjacent reactive marrow and soft tissue edema. This image shows a well circumscribed lesion with peripheral hypointensity in the central intercondylar notch with adjacent reactive marrow edema. Peripheral rim of low intensity with lobular central regions of heterogeneous low, intermediate and high T2 signal. Areas of low signal intensity from immature chondroid matrix, calcification, increased cellularity, and hemosiderrin. Notice the exuberant high T2 signal surrounding the lesion. Greater marrow and soft tissue enhancement adjacent to tumor than within tumor itself. Image demonstrates the same inter-condylar lesion with internal and adjacent marrow and soft tissue enhancement. Sheets of chrondroblasts with reactiveGiant cells and chondroid matrix. Rare lesion accounting for <1% of primary bone tumors found most commonly in patients <30 years of age. ~30% contain internal chondroid matrix and ~50% have associated periostitis in a metadipahyseal location. Sclerotic margin aids in differentiation from Brodie's abscess and EG which can also be seen in epiphyses. ~30% display internal chondroid matrix and ~50% have associated periosteal reaction in the metadiaphysis. Often associated with a large amount of marrow and surrounding soft tissue edema
Chondromyxoid fibroma Lytic lesion, eccentrically positioned in metaphysis oriented along long axis of bone. Cartilaginous matrix rarely seen Axial section through tibial diaphysis demonstrating a well-defined, expansile, lytic lesion without periosteal reaction. Lesions are well defined, usually cortical based in long bones and demonstrate isointense T1 signal intensity. Lesions are hyperintense on T2 weighted images will mild surrounding soft tissue edema. No marrow edema is noted. Chondroid, fibrous, and myxoid tissue mixture. Eccentrically located metaphyseal lytic lesion without periosteal reaction seen in 20-30 year old patients. Oriented along long axis of bone. ~80% in long bones and majority occur in femur/tibia. Similar to NOF but can extend into epiphysis. Cartilaginous lesion but cartilaginous matrix rarely seen.
Infection/Osteomyelitis Lytic lesions with high degree of variability in aggressiveneness of appearance. Plain film findings usually lag behind clinical findings. Earliest changes include soft tissue edema. Later see focal areas of intraosseouslucency eventually becoming confluent, corresonding to regions of bone destruction. Sequestra appear as sclerotic regions of dead bone. Images: 1) Lytic lesion in distal femoral diaphysis with associated sequestrum (differential diagnosis for sequestrum includes: Osteomyelitis, fibrosarcoma, lymphoma, EG).

2) Brodie's abscess
Sequestrum seen within cortex of focus of infection in distal diaphysis of left femur. Ill defined regions of decreased T1 marrow signal. Image shows low T1 signal intensity in the marrow of the first metatarsal stump in a diabetic patient status post amputation. Short arrows demonstrate periosteal reaction, curved arrow demonstrates abscess formation. Long straight arrow at distal second metatarsophalangeal joint demonstrating a focus of septic arthritis.

Brodie's abscess
1) High T2 signal within marrow with high signal sequestrum seen within cortex of distal femoral diaphysis.

2) Brodie's abscess
Solid enhancement of phlegmonous change with peripheral enhancement around abscess. Image shows a distal fibular subperiosteal abscess.

Brodie's abscess
Triple phase technetium-99m MDP bone scan combined with Indium-111 labeled WBC (for appendicular skeleton) or Gallium-67 (for spinal infection) is highly sensitive for detecting early osteomyelitis when plain film findings have not yet become apparent. Findings include increased uptake on blood flow, blood pool, and delayed/bone phases of bone scan with increased uptake on Indium-111 WBC scan. Increased uptake on the first two phases indicates hyperemia, increased uptake on the third phase localizes the inflammation to bone, and increased uptake of Indium labeled WBCs increases specificity further for osteomyelitis as conditions with high bone turnover including tumor, joint neuropathy, and fracture can mimic osteomyelitis on the first three phases. Most common in children via hematogenous dissemination to bone (epiphyses in neonates, metaphysis in older children due to differing vascular localizations at different ages) with centrifugal spread of changes first involving marrow-cortex-periosteum-soft tissue. In adults, most commonly via spread of adjacent soft tissue infection, thus changes are centripetal in sequence first involving periosteum, cortex, then marrow. Findings can include: sequestra - regions of devitalized cortical bone surrounded by normal bone. Involucra - regions of periosteal thickening surrounding dead/infected bone. Cloaca - an opening in involucrum allowing drainage of pus from sequestrum and other reagions of infected bones. Sinus tracts- drainage pathways from infected bone to skin surface. Brodie's Abscesses-seen in subacute/chronic infections involving organisms of low virulence resulting in localized areas of walled-off infection with peripheral sclerosis and central lucency.
Multiple Myeloma Radiographic bone survey remains mainstay of diagnostic workup. Findings in ~75% of myeloma patients with ~50% bone destruction necessary for detection on xray. 4 main forms: 1) Solitary lesion (plasmacytoma-typically in ribs, pelvis, spine, skull, sternum, proximal extremities), 2) Diffuse lesions (myelomatosis-lytic lesions with well-defined margins of uniform size- may coalesce into larger areas of destruction. Typically subcortical/ eccentric in location and ellipsoid in shape), 3) Diffuse osteopenia (most pronounced in spine with associated compression fractures), 4) sclerotic (associated with POEMS syndrome- Polyneuropathy, Organomegaly, Endocrinopathy, Myeloma (sclerotic), Skin changes).
1) Myeloma in skull.

2) Myeloma in humerus

3) Myeloma-related vertebral body compression fracture

4) Plasmacytoma in rib
Punched-out lytic lesions, expansile lesions with soft tissue masses, diffuse osteopenia, fractures, and osteosclerosis (rarely). Useful adjunct to plain films and MR in defining and biopsying lytic and sclerotic lesions.

2) Transpedicular biopy approach of lytic myeloma lesion in T9 vertebral body.
Good in demonstrating degree of marrow involvement with improved characterization of spacial relationship with and compression of soft tissue structures. Plasmacytomas are generally hypointense lesions within surrounding normal hyperintense fatty marrow. Diffuse disease often manifests as diffusely hypointense marrow signal compared to intervertebral disks or muscle. Sagittal images of normal marrow (top), diffuse myeloma (middle) with homogeneous infiltrative disease, and (bottom)heterogeneous marrow infiltration. Focal lesions are hyperintense relative to marrow on STIR while diffuse disease manifests as diffusely hyperintense marrow signal compared to muscle. Images: 1) Multiple plasmacytomas within vertebral bodies and posterior elements of thoracic spine with cord compression.

2) Sagittal images of normal (top) marrow, diffuse myeloma (middle) with homogeneous infiltrative disease, and (bottom)heterogeneous marrow infiltration.

3) Myeloma on T2 FS
Enhancement seen in both focal and diffuse forms of disease. Enhancement may be homogeneous or heterogeneous depending upon degree of marrow infiltration. Sagittal image of normal marrow (top), diffuse myeloma (middle) with homogeneous infiltrative disease, and (bottom) with heterogeneous marrow infiltration Bone scanning agents rely on osteoblastic activity in lesions, and thus are not sensitive in detecting osteolytic lesions of myeloma unless associated with pathologic fractures with resultant increased reparative osteoblastic activity. Gallium-67 citrate, Thallium-201 chloride, Technetium-99m Sestamibi, and Flourine-18 FDG PET accumulate in lytic lesions with good sensitivity. FDG PET images before and after therapy. Well-defined subpleural lesion with associated periosteal reaction of adjacent rib Hematologic malignancy of terminally differentiated B lymphocytes into plasma cells of monoclonal origin. Should be on differential for lytic lesions in patients greater than 40 years old (median age 65, 3% in pts less than 40). More common in males and African Americans. Lytic bone/soft tissue lesions, renal failure, anemia, hypercalcemia.
Metastases Nonspecific lytic lesion which may have aggressive or non-aggressive features. This image shows an expansile lytic lesion within the cortex of the tibia in a patient with a history of RCC.

Lesser trochanter met
Metastatic disease on bone windows

Metastatic disease on soft tissue windows

Additional met on CT
Metastatic disease on T1 In general, mixed T2 intensity lesions with some element of increased T2 signal. This sagittal STIR image through a proximal tibial metastatic RCC lesion shows diffuse T2 hyperintensity within the lesion. Purely lytic lesions will show no uptake on bone scans unless there is an element of reactive osteoblastic activity. In this case of lytic metastatic RCC, bone scintigraphy shows diffuse radiotracer uptake in a metastatic lesion in proximal tibia indicating increased osteoblastic activity in the region. Resected proximal tibia with hemorrhagic and lytic metastatic focus. Corresponds to pathology of primary tumor. This image demonstrates a focus of metastatic lytic renal cell carcinoma. Must be included on differential for patients older than 40 years old with lytic lesion regardless of whether lesion appears aggressive or not. Most common primaries include Breast, Lung, Thyroid, Kidney, Prostate. Most common lytic metastases include breast, lung, renal, thyroid, colon and (in children) neuroblastoma. Breast and lung have both lytic and sclerotic metastases. Prostate cancer usually associated with sclerotic metastases.