Author: Micah Cohen Radiograph CT MRI - T1 MRI - T2 or STIR MRI - Post-contrast T1 Radionuclide Gross Pathology Histology Additional comments
Fibrous dysplasia Ground glass matrix. Lesion within marrow, can be eccentric with sclerotic rim. Example: polyostotic fibrous dysplasia with diffuse involvement of pelvis. 1) middiaphyseal femoral lesion with expansion of medullary cavity & ground glass matrix.
2) large lytic lesion with expansile remodeling of left ilium & faint ground glass matrix
mildly heterogenous signal intensity, in majority comparable to muscle, within expansile lesion within left ilium homogeneously increased signal intensity in expansile lesion within left ilium Markedly increased radionuclide uptake in polyostotic fibrous dyspasia with involvement of ribs, pelvis, shoulders, hemicranium on technetium-99m methylene diphosphonate scan proximal femur with classic shepherd's crook deformity. Arrows point to multiple dysplastic fibrocartilaginous islands within expanded marrow cavity Myxofibrous tissue containing woven bony trabeculae Typically <30 years old. Mono- & polyostotic forms. Associations:  McCune Albright, Mazabraud, Cherubism (symmetrically in maxilla & mandibles of children
             
Adamantinoma Elongated, multilocular lytic lesion with narrow zone of transition within the tibial marrow cavity w/associated endosteal scalloping & cortical expansion. No periosteal rxn. Intermediate signal intensity lesion. Hyperintense STIR signal. Intense post contrast enhancement. 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 malignant lesion of the tibia/fibula. Age 10-20 year olds. Periosteal rxn in only ~15%. Narrow zone of transition. Synchronous lesions in fibula seen in 5-10%. Similar in imaging to osteofibrous dysplasia.
             
Eosinophilic Granuloma Radiographic findings depend on stage of disease. Early: lytic, ill-defined margins, periosteal rxn. Later: well defined w/sclerotic rim & expansion/remodeling. Lytic lesions may contain a sequestrum. Skull lesions: "beveled" appearance w/asymmetric involvement of calvarial tables. Multiple lesions coalesce to form a "geographic skull". Spares posterior elements in spine. Vertebra plana. Helpful in defining extent of osseous destruction and involvement of soft tissue. Hypointense marrow replacing lesion Hyperintense bone marrow replacing mass 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 & arc appearance. Example: Multiple soft tissue calcifications representative of phleboliths associated w/hemangiomas (Maffuci's syndrome).
2) Ring & arc matrix appearance in proximal humerus enchondroma w/associated shallow endosteal scalloping.
Axial section through distal femoral enchondroma revealing chondroid matrix and shallow endosteal scalloping. 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: Multiple encondromatoses w/soft tissue hemangiomas (higher rate of malignant transformation).
Ollier's disease: Multiple encondromatoses.  
               
Giant Cell Tumor Example: eccentrically located, lytic lesion in distal femoral epiphysis. Narrow zone of transition. Nonsclerotic rim. Often displays multiloculated appearance from prominent trabeculation. 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. Intermediate T2 signal may be related to hemosiderin and/or increased cellularity or high collagen content.  Solid enhancing hypervascular elements of GCT with peripherally enhancing elements around secondarily formed ABC. Increased radiotracer uptake in distal femoral epiphysis on lateral projection of bone scintigraphy. 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.  Must meet 4 criteria: 1) closed epiphyses 2) abuts  articular surface 3) eccentrically located 4) narrow zone of transition w/nonscelrotic rim (can have sclerotic rim in flat bones).  Periosteal rxn uncommon. Most common lesion associated w/2nd aneurysmal bone cyst formation. No internal mineralization.
               
Nonossifying fibroma Smoothly marginated, cortically based lesion of distal femoral metaphysis, with sclerotic rim and no periosteal reaction. Lesion can appear lytic early on and dense during "burnt out phase" Intermediate intensity surrounded by low intensity sclerosis. Low intensity sclerosis surrounding variable intensity mass. More often hypointense than hyperintense. Mass is hyperintense on this STIR image with peripheral low intensity sclerosis. 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. AKA fibroxanthoma or fibrous cortical defect when <3cm. Most common in children. Cortically based lesions with thin rim of sclerosis, scalloped borders, and no periosteal rxn. Natural course is involution with progressive sclerosis.
           
Osteoblastoma (1) Here, we see a lucent expansile lesion involving the spinous process and laminae of C3 on a lateral radiograph with mild sclerosis suggestive of internal mineralization. 3 classic patterns: i. central lucency with peripheral sclerosis-
ii. Calcified expansile lesion with sclerotic rim.
iii. Osseous expansion, bone destruction, extension into soft tissues, internal matrix calcification-more aggressive lesion.


(2) Well defines lucent lesion in proximal humerus with peripheral sclerosis and expansion of cortex.
1.Expansile lesion involving posterior elements of Cervical spine with sclerotic rim and protrusion into spinal canal.

2. Axial image through proximal humerus showing a cortically based lytic lesion with expansion of cortex and medullary sclerosis.
Low to intermediate signal. 1. Intermediate to high signal. Peripheral hypointensity from sclerosis.

2. High signal intensity, lobulated, cortically base lesion in proximal humerus.
Expansile, lobulated mass with whitish tissue representing osseous matrix. 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). ABC component seen in 10-15% Three classic radiographic patterns (see plain film cell)
             
Aneurysmal Bone Cyst 4 radiographic stages:1)Initial-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. 2. Expansile, multiloculated lytic lesion of the second metacarpal. Well-defined lytic lesion with internal septations. 35% display fluid-fluid levels-indicative of hemorrhage with sedimentation. This image shows a well-defined, multiloculated lesion with peripheral calcifications and fluid-fluid levels from layering hemorrhagic components in the lumbar spine. 1. Well-defined lesion with internal septation and may display fluid-fluid levels. Foci of hyperintensity from metHB. Low signal rim from intact, thickened periosteal rim. 2. This image comes from the distal humerus a 4 year old male with a multiloculated, expansile lesion which demonstrates high T1 signal components. Heterogeneous intensity from evolving blood products with predominantly areas of hyperintensity. Low intensity rim from intact and thickened periosteal rim. Smooth enhancement of internal septations. Enhancement of other solid components may indicate association with a preexisting lesion. 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 Lytic, expansile lesion in distal femoral metadiaphysis with associated "fallen fragment" sign and pathologic fracture. Axial section through distal femoral metaphysis displaying expansile lytic lesion with fragment of bone and pathologic fracture. Bright T2 signal with fluid levels in a proximal humerus metadiaphyseal lesion Lytic, 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) and pathologic fractures.
     
Hyperparathyroidism/Brown's Tumor Well-defined lytic 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. Healing lesions may appear sclerotic. Look for other associated signs of hyperparathyroidism (see "additional comments" cell) Well-defined lytic, expansile lesion in mandible. 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 lytic lesion in epiphysis/apophysis with sclerotic margin. 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. This image demonstrates an eccentrically positioned, well-defined lytic lesion with a sclerotic rim within the greater trochanter. Eccentric, well-defined lytic lesion in epiphysis/apophysis with sclerotic margin. Sclerotic margin aids in differentiation from Brodie's abscess and EG which can also be seen on epiphyses. ~30% display internal chondroid matrix and ~50% have associated periosteal reaction in the metadiaphysis. Axial CT image through left distal medial femoral condyle shows a well-defined eccentrically located lytic 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 greater trochanter with adjacent reactive marrow edema. Peripheral rim of low intensity with lobular central regions of low, intermediate and high T2 signal. Areas of low signal intensity from immature chondroid matrix, calcification, increased cellularity, and hemosiderrin. Greater marrow and soft tissue enhancement adjacent to tumor than within tumor itself. Image demonstrates a greater trochanter lesion with internal and adjacent marrow and soft tissue enhancement. Sheets of chrondroblasts with reactiveGiant cells and chondroid matrix. Rare lesion accounting for less than 1% of primary bone tumors found most commonly in patients less than 30 years of age. Vast majority occur in long bones and are eccentrically positioned within eiphyseal/apophyseal location with some occurring in metaphyses. ~30% contain internal chondroid matrix and ~50% have associated periostitis in a metadipahyseal location. 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 proximal left humeral diaphysis demonstrating a well-defined, expansile, lytic lesion without periosteal reaction. 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) Thick periosteal reaction surrounding expansile lytic lesion in right radius.
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. 1)High T2 signal within marrow with high signal sequestrum seen within cortex of distal femoral diaphysis.

2) Low signal intensity sequestrum surrounded by high signal intensity within the cortex with adjacent fluid and periosteal reaction (involucrum).
Solid enhancement of phlegmonous change with peripheral enhancement around abscess. Image shows a distal fibular subperiosteal 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)AP radiograph of femur demonstrating well-defined myeloma lesion.


2) Multicystic appearing lytic lesion in C6 vertebral body extending into neural arch.
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. Images: 1)This sagittal image through the thoracic spine displays multiple compression fractures of thoracic vertebral bodies with a lytic lesion in T1 and resultant exaggeration of the thoracic kyphosis.

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.
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. Lytic mass in anterior tibial plateau with destruction of cortex. Top image shows primary renal cell carcinoma in right kidney. 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.