Benign bone lesions
| Site | Size | To Bone | Bone response | Matrix | Cortex | Soft Tissue | Age | Class | Pathology | DDx | Other | Rx |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
?Long bones & post elements | Nidus < 1cm, if > 2cm = osteoblastoma | (subperiosteal = ±scalloping) | Cortical/medullary = intense sclerosis | ± calcified central nidus | thickened | none | 10 to 35 | Benign active | Osteoid with fibrovascular tissue between trabeculae | Stress #, Brodie’s abscess, osteoblastoma, bone island (cold bone scan) | Pain relieved by NSAIDs, scoliosis, hot bone scan | None, NSAIDs, curettage, ablation, en bloc | |
?post elements, met/dia of long bones, skull | > 2 cm, progressive | Usually lytic, also sclerotic, resemble ABC if lytic | Geographic, sclerotic rim, ±neocorticalization | Poorly visible osteoblastic, bone if small | Aggressive can erode | Neocorticalization if present | 10 to 35 | Benign aggressive | Trabeculae in fibrovascular stroma, may coexist with GCT or ABC | OO, ABC (esp. spine), GCT, Brodie’s, osteosarc, chondrosarc, chondroblastoma (epiphyseal) | Hot bone scan, difficult to differentiate from osteosarc | En bloc or curettage/bone graft/cement, (RR = 10 – 20%) | |
Bone surface, calvarium | Variable | Focal, dense, homogenous bone, geographic | None | Sclerotic | Smooth, merge | none | Dx in 5th dec | Benign hamartomatous | Heavily ossified tissue | Parosteal osteosarc, osteochondroma, periostitis, met | Assoc. with Gardner’s synd (auto dom, intestinal polyposis, ST fibromas, sebaceous cysts) ? fibrosarc, ampulla of Vater carcinoma, thyroid Ca | Excise if symptomatic | |
Osteochondroma (“exostosis”) | Metaphyseal, knee, shoulder, hip | variable | Metaphysis may be expanded and remodeled | Remodelling | Enchondral ossification of cartilage cap, cartilaginous matrix prior to maturity | Contiguous marrow cavity, grows away from epiphysis | Non-ossified cartilage cap >1 or 2 cm in an adult suggests malignant transformation (chondrosarcoma) | 10 to 35 | Benign latent, parosteal or surface lesion | Cartilage cap matures into trabecular bone | Juxtacortical myositis ossificans, periosteal chondroma, surface or soft tissue osteosarcoma | Assoc. with familial osteochondromatosis, MRI shows thickness of cartilage cap, CT shows contiguous marrow, malignant transformation risk 1% for solitary, higher more proximal | Asymptomatic = no treatment, excise if painful or NV compression, recurrence rate if immature |
Metadiaphysis, femur, humerus, diaphyseal in hand (prox phal > MC > mid phal > dist phal | 3 to 5 cm, smaller in hands and feet | Minor endosteal erosion, hand lesions may be quite aggressive but are still benign | Geographic, little endosteal response | Popcorn calcification in long bones, radiolucent in hand and foot | Cortical erosion usually only in hand and foot | None, rarely enchondroma protuberans in hand | 15 to 40 | Benign latent, except pathologic # in phalanges | Well-circumscribed lobules of cartilage | Medullary bone infarct, GCT in metacarpals, fibrous dysplasia, UBC, chondrosarcoma | Assoc. with Ollier’s and Maffucci’s, worrisome = endosteal scalloping, permeative lucency, rare malignant transformation | Biopsy if change with time, persistent pain, worrisome Xray features. Xray @ 3, 6 12 months. Curettage & BG | |
Proximal tibia, distal femur, metaphyseal, eccentric | 3 to 10 cm | radiolucent | Geographic, sharp sclerotic margin | Not usually seen | Cortical erosion or ballooning | None | 10 to 30 | Benign aggressive cartilage lesion | Firm, tan tissue with lobular pattern, myxoid or chondroid matrix | GCT, ABC, UBC, nonossifying fibroma, chondroblastoma, infection, osteoblastoma, Brown tumour, telangiectatic/chondroblastic osteosarcoma |
| Biopsy, curettage & BG or marginal excision, recurrence < 20% | |
Epiphyseal/apophyseal, femur > humerus > tibia > pelvis > tarsal bones | Variable | Lytic lesion with geographic margin | Sclerotic rim of reactive bone | Lytic, possible internal cartilaginous calcifications | Expansion if metaphyseal | None | 5 to 25 | Benign aggressive giant cell and chondroid type lesion | Proliferating chondroblasts, chondroid matrix (pink not blue), numerous giant cells | Degenerative joint cyst, enchondroma, clear cell chondrosarcoma, GCT | GCT is usually epiphyseal-metaphyseal and has no calcifications, no ossifications, and no sclerotic margin | Thorough curettage & BG, recurrence 10 to 30% | |
Eccentric, subperiosteal, external to cortex, metaphyseal cortex of long bones, esp. prox humerus, tibia, femur, and small tubular bones of hands and feet | Variable | Periosteal, causes cortical erosion | Well defined, shallow, geographic, peripheral periosteal elevation and reaction | Radiolucent, scattered calcifications | Cortical erosion | always | 2nd to 4th decades | Benign active, slow growing, rare | Hyaline cartilage, nodules on surface of the cortex | Periosteal chondrosarcoma or osteosarcoma, adjacent soft tissue neoplasm |
| En bloc resection, narrow margin | |
Periarticular, intra-articular loose bodies, knee >> hip, shoulder, elbow, ankle | Multiple calcified bodies, mm to cms | Degenerative arthritis | Mild reactive sclerosis from bone erosion | Cartilage +/- calcification/ossification | N/A | Extension into bursae around distended joints | 3rd to 5th decades | Benign cartilaginous lesion | Nodules of chondroid tissue both free and within synovium | Loose bodies: secondary osteochondromatosis, osteochondral #, OA, Charcot, osteochondritis dessicans |
| Remove loose bodies, total synovectomy | |
Distal femur and tibia, eccentric, cortical, metaphyseal | < 4cm | Radiolucent, elliptical | Sharp demarcation, thin sclerotic margin | none | Entirely a cortical lesion | None | Age 4 to 8 | Benign latent | Cortex replaced with fibrous tissue, spindle cell proliferation, storiform pattern, giant cells, ++iron (Prussian blue) | Infection, chondromyxoid fibroma, fibrous histiocytoma, nonossifying fibroma | Symptomatic almost exclusively in children, spontaneously resolves with cessation of growth | Observation, 3,6,12 months if lesion atypical | |
Tibia and femur, expands into medullary cavity | > 4cm | Fracture risk as enlargens | Thin, sclerotic, lobulated margin | None | Expanded and thinned | None | <30 | Benign latent or active | Identical to fibrous cortical defect | ABC, fibrous dysplasia, chondromyxoid fibroma | Arises from a fibrous cortical defect that enlarges into metaphysic, most lesions spontaneously heal | Curettage & BG +/- ORIF if: atypical location, questionable diagnosis, intractable pain, impending path # | |
Fibrous dysplasia – monostotic | Ribs > femur > tibia > maxilla > mandible > skull > humerus, usually spares epiphysis but can be throughout bone | Variable, can involve entire bone | Lytic to ground glass, endosteal expansion | Well-demarcated sclerotic border, limited periosteal response | Osseous matrix if present can produce ground glass appearance | Endosteal erosion | None | Late childhood into adulthood | Benign latent, active, or aggressive | Cellular fibrous tissue with immature woven bone “Chinese character” shapes | UBC, nonossifying fibroma, solitary EG, ABC, GCT, hemangioma, infection, central low-grade osteosarcoma, fibrosarcoma, Ewing’s | Fibrous dysplasia is the third most common cause of secondary osteosarcoma arising in diseased bone after Paget’s and radiation | Biopsy may be required for diagnosis, bracing, activity modification |
Fibrous dysplasia – polyostotic | Femur > craniofacial bones > tibia > humerus > ribs > fibula | May progress in size and number until skeletal maturity | Geographic, more aggressive than monostotic | Endosteal expansion | Same as monostotic | Fusiform expansion of cortex | None | Younger than monostotic, esp. if endocrine disorder |
| Same as monostotic | Multiple enchondromatosis, Paget’s, Brown tumour, metastasis, von Recklinghausen’s (NF, café au lait), MM, EG | Earlier onset = more progressive, 25% polyostotic, assoc. with McCune-Albright syndrome | Bone scan useful for detecting multiple lesions, can usually be diagnoses on Xray |
Ossifying fibroma = Osteofibrous dysplasia = Kempson-Campanacci | Usually proximal anterior tibia, eccentric, diaphyseal | Variable | Osteolytic | Blister-like areas of cortical lucency surrounded by dense sclerosis, geographic | radiolucent | Intact and expanded | None | <20 | Benign active or aggressive | Woven bone trabeculae in fibrous stroma | Adamantinoma (age), fibrous dysplasia, nonossifying fibroma, osteoblastoma, ABC | Very rare, can progress to adamantinoma | Observe if asymptomatic, high recurrence if <10, excision & BG |
75% in epi/metaphysic of long bones, 50% around knee, distal radius, prox humerus, vertebrae, sacrum | Usually >50% bone diameter | Lytic, geographic, often extends to subchondral bone | Expansile, usually non-sclerotic | None | Neocorticalization if perforates cortex | Almost always occurs by eroding through cortex (as opposed to Ewing’s), 20% | 80% > 20 years old, <5% with open plates | Benign aggressive, rarely metastatic (5%) | Multinucleated giant cells, hemosiderin = low signal on both T1 and T2 | ABC, Brown tumour (Serum Ca), telangiectatic osteosarcoma, fibrosarcoma, osteoblastoma | Campanacci stages: | Expendable bone = wide en bloc, non-expendable = curettage, adjuvant phenol/Nitrogen, BG or cement, 10-25% recur | |
Spine (esp. post), femur, tibia, metaphysic of long bones, usually eccentric, can be diaphyseal | Variable, usually > 5cm | Lytic and expansile | Marginal sclerotic rim, neocorticalization | None | Eroded | Generally contained lesion | <30, 80% <20 | Benign aggressive, not metastaic | Hemorrhagic cystic tissue, lacks endothelial cell lining, walls are fibrous tissue and giant cells | UBC (generally central), GCT (may co-exist), osteoblastoma, telangiectatic osteosarcoma | ABC and osteoblastoma both appear in posterior spine, MRI = multicystic, fluid-fluid level, markedly expansile | Open biopsy, curettage & BG/cement, recurrence 10-20%, en bloc in expendable bone | |
Central medullary lesion, thought to begin in metaphysic and migrate to diaphysis, 80% = prox humerus or prox femur, also ilium, calcaneus, talus | Can be quite large | Lytic, lobulated borders | Geographic, thin sclerotic margin | None | Often circumferential endosteal erosion | None | 80-90% < 20, younger = more active | Benign latent or active lesion of bone | green-yellow fluid, wall is fibrous tissue | ABC, fibrous dysplasia, chondromyxoid fibroma, telangiectatic osteosarcoma, infection, nonossifying fibroma | Fallen leaf sign = cortical fragment falls into lesion in path #, MRI = fluid-fluid only if path #, minimal bony expansion | Plain films and aspiration usually diagnostic, open biopsy if no fluid or hemorrhagic | |
Diaphyseal or metaphyseal, skull, ribs, vertebrae, pelvis, and long bones (mostly femur and humerus), almost never hands or feet | Variable | Lytic, can be patchy, long bone expansion less common, path # common in spine (vertebra plana) | Commonly geographic, minimal metaphyseal sclerosis, may be periosteal reaction or onion skinning | None, except hazy matrix at resolution stage | Thinned, scalloped, onion skinning | Rarely | 5 to 10, rare after 30 | Benign active or aggressive, can be multiple, tumour-like disorder, belongs to Langerhans’ cell histiocytoses | Friable tan tissue, histiocytes, Langerhans’ cells (S100+, Birbeck granules on EM), eosinophils, giant cells | UBC (usually metaphyseal, larger, less painful), osteomyelitis, | Often heals spontaneously (months to years), | Indications: 1.diagnosis, 2.persistent pain, 3.prevention or treatment of pathologic fracture. | |
Spine > craniofacial > femur or humerus > hands and feet | Variable | Vertebrae = vertical striations (corduroy), honeycombing | Rarefaction, reactive ossification | None | “disappearing bone disease”, ballooning | Rarely | 40 to 60 | Benign latent or active, often incidental | Hemorrhagic, vessels, dilated capillaries between bone trabeculae | Spine = Paget’s (picture frame appearance, expansion), myeloma, metastasis | Gorham’s disease (massive lysis that can cross joints) | Asymptomatic = no treatment, vertebra collapse treated if neuro deficit, chronic pain, pre-op embolization |
Familial Osteochondromatosis
- Autosomal dominant, variable penetrance
- 30% spontaneous
- Short stature, unequal growth of radius and ulna – Madelung deformity (radial deviation of the hand due to ulnar plus), unequal growth tibia and fibula – valgus knees and ankles
- Long bones, pelvis, ribs, scapula, distal ends of proximal and distal phalanges
- Monitor for malignant change
Ollier’s disease = multiple enchondromatosis
- Inborn error of osseous development
- non-hereditary
- Often unilateral, metaphysic & diaphysis
- Deformity, growth disturbance
- 25-30% risk of transformation to low- or intermediate grade chondrosarcoma
Maffucci’s syndrome
- Congenital, non-hereditary
- Multiple enchondromas and multiple soft-tissue hemangiomas
- Calcified phleboliths
- Higher risk of malignant transformation than Ollier’s
McCune Albright syndrome
- Polyostotic fibrous dysplasia – tendency to be unilateral
- Café au lait spots – midline neck, chest, shoulders, sacrum, rough borders unlike NF
- Multiple myxomas
- Endocrine disturbances – Cushing’s, hyperthyroidism, acromegaly, various adenomas
- Classically present with precocious puberty and short stature
Letterer-Siwe Disease
- Associated with EG
- Acute, fulminant disease affecting infants < 2
- Hepatosplenomegaly, adenopathy, CNS involvement, fever, anemia, thrombocytopenia
- Potentially fatal
- Treated with corticosteroids and chemo
Hand-Schuller-Christian disease
- Develops in <20% of patients with EG
- Onset usually 5 to 10 years old, rarely sooner
- Exophthalmos (retro-orbital invasion), diabetes insipidus (sphenoid invasion), skull defects (classic triad < 10% of patients)
Malignant bone lesions
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| Site | Size | To Bone | Bone response | Matrix | Cortex | Soft Tissue | Age | Chemo/rad | Pathology | DDx | Other | Rx |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Osteosarcoma | Central Osteosarcoma | Conventional (75%) | Metaphysis, may extend across physis, distal femur, proximal tibia, proximal humerus, flat bones | Large (>5 cm) | Permeative, patchy lytic/sclerotic | Sunburst, Codman’s triangle, no marginating reaction | Osteoid with variable sclerosis | Erosion | May occur without cortical destruction, poorly organized bony matrix | 2 to25; | Methotrexate, adriamycin, cisplatin, ifosphamide | Osteoid in lace-like, or sheet-like pattern, cells spindle, epithelioid, or small and round | GCT, ABC, Ewing’s, osteoblastoma, mets, lymphoma | Alk phos, LDH often elevated, local recurrence is almost always associated with metastases, removal of lung mets often prolongs survival, radiation ineffective | Biopsy with MSK oncologist, neoadjuvant chemotherapy prior to limb salvage, 5-yr survival 50-85%, |
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| Telangiectatic | Metaphysis femur, tibia, humerus |
| Lytic, expansile, rarely permeative | +/- periosteal reaction |
|
| Usually, with hemorrhage |
| Chemo-responsive |
| ABC, GCT, Brown tumour, osteoblastoma |
| Similar to conventional |
|
| Low-Grade | Most metaphysis of long bones, less diaphysis | Large | Lytic with internal sclerosis/ trabeculations | Wide zone of transition |
|
| Not usually | Young adults, mean 30 |
| Difficult to diff from fibrous dysplasia, minimal atypia | Fibrous dysplasia, fibrosarc, infection, lymphoma | Better prognosis than conventional, rare path # |
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| In Pagetoid Bone |
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| 46 to 91 |
| Usually high grade |
| Also chondrosarc, fibrosarc, MFH | Prognosis worse: large, axial, older (no chemo) |
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| Small Cell | Metaphyseal distal femur, humerus |
| Sclerotic or mixed, permeative | Codman’s |
|
| Usually | 10 to 30 |
| Sheets of small, round, blue cells | Ewing’s |
| Rare, differs from Ewing’s by making osteoid |
| Surface | Parosteal | 2/3 post distal femur, prox medial humerus, lat prox tibia | Large | “Applied” to bone (plasticine), may encircle |
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| Juxtacortical sclerotic mass, lobulated large base |
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| Chemo if high grade | Fibrous, osseous, cartilaginous elements. Often low-grade, well-formed trabeculae | Periosteal osteosarc or chondrosarc, myositis ossificans, exostosis | Highest osteosarcoma prognosis | Biopsy with MSK surgical oncologist, wide resection, chemo if high grade |
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| High-Grade Parosteal (Dedifferentiated) | 2/3 post distal femur, prox medial humerus, lat prox tibia | Large |
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| Maybe | ” | Chemo |
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| Rare | Similar to central |
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| Periosteal | Metaphyseal and diaphyseal femur and tibia |
| Destructive, periosteal reaction, Codman’s | Periosteal new bone in spiculed pattern | Stippled calcification, denser at base | Scooped out |
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| Chemo if high grade | Generally low grade | High-grade surface osteosarc, periosteal chondrosarc, Myositis oss. |
| Wide excision |
Chondrosarcoma | Central |
| Prox/dist femur, prox humerus, scapula, pelvis | >5 cm, variable | Geographic, destruction proportional to grade | Endosteal expansion | Punctuate calcifications | Endosteal scalloping, maybe cortical thickening | More in high grade | 30-70 | Not effective primary therapy, rads can be used if wide resection not possible | Myxoid or chondroid, binucleate cartilage cells, grade determined by atypia | Enchondroma, osteosarc, fibrosarc, MFH, mets, chordoma if sacrum | More distal location is more likely benign, lung mets can be years after | Biopsy with MSK surgical oncologist, wide resection |
| Periosteal |
| Surface |
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| May invade canal |
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| Periosteal chondrome, periosteal osteosarc |
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| Clear cell |
| Epiphysis or metaphysic of long bone, esp. prox femur and humerus |
| Lytix, geographic | Sharp sclerotic margins | uncommon | Intact but may be expanded |
| 20-40 |
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| chondroblastoma | Rare, low grade, can metastasize | Wide resection |
| Mesenchymal |
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| Lytic, destructive, permeative |
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| 10-30 | Sometimes chemo | Small, round, blue cells with chondroid |
| Rare, high grade, poor prognosis | Wide resection |
| Dedifferentiated |
| Similar to central |
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| Similar to central |
| Mix of chondrosarc with fibrosarc or MFH |
| Rare, high grade, usually mets by 2 yrs | Wide resection |
Fibrosarcoma |
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| Pelvis, dist femur, prox tib, prox humerus, central > eccentric | Usually > 5cm | lytic | Permeative, no sclerosis | radiolucent | Thinned, destroyed, maybe periosteal rxn | Common in high grade | 20-60 | No. | Herringbone pattern spindle cells, atypia | MM, solitary met, GCT, MFH, dediff chondrosarc, (Ewing’s if < 25) |
| Biopsy with MSK surgical oncologist, wide resection |
MFH |
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| Metaphysic of long bones, 50% in femur | Usually > 5cm | Lytic, destructive | Permeative, but may have sclerotic margin in low grade | rarely | Erosion | Usually | Bimodal 50-60, and 20-30 | Neoadjuvant and adjuvant chemo | Malignant spindle cells in storiform pattern, mix of giant cells, histiocytes |
| Unknown cell of origin | Biopsy with MSK surgical oncologist, wide resection, chemo |
Last Updated on September 27, 2026
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