CAM III - Ortho Neoplasms

osteoid osteoma

MC benign osteoid tumor, usually occurs in long tubular bones (proximal femur MC site), M>F in 2nd decade of life, presents with dull, aching, nocturnal pain completely relieved with NSAIDs; early stage can be treated symptomatically, surgical removal or surgical ablation if later stage

XR: central, lytic nidus 1 cm or less with sclerotic reactive surrounding

osteoblastoma

large osteoid osteoma, common in posterior aspects of spine, M>F in second decade of life, treated with vigorous curettage of the lesion (possible bone graft)

XR: more lytic and destructive lesion, nidus >1-2cm with less sclerotic boundary

osteofibrous dysplasia

rare condition, usually seen in the tibia of children (M>F) in first two decades of life, can also be seen in bilateral fibula, difficult to differentiate from adamantinoma, often arrests around age 15 (wait until this age to operate)

XR: lytic changes in anterior tibial cortex surrounded by sclerotic margins ("soap bubble appearance")

enchondroma

centrally located chondroma of bone, MC in bones of hands/feet, frequently asymptomatic even into adulthood, large lesions can convert to low-grade chondrosarcoma during adulthood (5%), should be observed with serial radiographs

XR: geographic lysis with sharp margination and central calcification

periosteal chondroma

benign chondroma on surface of long bone, frequently have multiple lesions, MC location on proximal humerus metaphysis, can grow to large size, treated with serial imaging to ensure no growth into adulthood

XR: appear to saucerize underlying cortex

osteochondroma

MC benign bone tumor, developmental or hamartomatous process arising from a defect of the outer edge of the metaphyseal side of the growth plate, lesions point away from joint and move away from physis with growth, stop growing with skeletal maturity, usually asymptomatic are do not require surgical treatment

chondroblastoma

benign cartilage forming tumor forming at epiphyses or apophyses, may form physeal scar when diagnosed at skeletal maturity, peak incidence in males in 2nd decade, long bones most affected

XR: sharp demarcation of radiolucent lesion in the epiphysis with stippled or flocculent calcification, can be erosion of subchondral bone with collapse of pathologic fracture

non-ossifying fibroma

larger form of fibrous cortical defect (at metaphyseal areas of LE in growing children), can lead to pathologic fracture, consider fracture prophylaxis for large lesions in children >10 years

simple bone cyst

common pseudotumor of the bone, frequent cause of pathologic fractures in children, MC in boys age 5-15 years, asymptomatic until fracture, treat aggressively if in weight-bearing bone, initial aspiration/injection with BM or corticosteroids repeated 3-5x every 2-3 months, sarcomas can have similar appearance (biopsy if indicated)

aneursymal bone cyst

hemorrhagic lesions with many characteristics of a giant cell tumor, mostly occur in females age 10-20 years, femur MC, confirm diagnosis with imaging and multiple site biopsy, frequently painful and swollen, may resolve spontaneously, can treat with surgical curettage and bone graft or repeated embolization

giant cell tumor of bone

occurs in third decade of life, more commonly in females, most often found above the knee, distal radius, sacrum, painful and can cause pathological fracture, can convert to osteosarcoma or malignant fibrous histiocytoma, can metastasize to lung, diagnosis of exclusion, treat with aggressive curettage procedure

XR: lytic lesion located at epiphyseal-metaphyseal end of long bone growing toward the articular cartilage

hemangioma

hamartomatous process, more frequent in females, common in vertebral bodies, can be associated with soft tissue hemangiomas, can cause cord compression and require surgical resection

XR: vertically oriented honeycombed or moth-eaten appearance

multiple myeloma

B-cell proliferative disease, MC primary malignant bone neoplasm in adults >40 years, high mortality rate, triad: osteolytic punched out lesions, proliferation of atypical plasma cells, monoclonal gammopathy; treated with chemo, steroids, bisphosphonates, surgery

osteosarcoma

uncommon, malignant tumor of bone, peaks in early adolescence and adults >65 years, RFs: irradiation/chemo, Paget's disease, fibrous dysplasia, genetic abnormality associated with retinoblastoma, has predilection for metaphyseal region of long bones, presents with localized pain over several months (wax/wane after injury), evaluate for metastasis to lungs

dx: elevated alk phos, LDH, ESR; MRI of bone, CT thorax, bone scan or PET scan, biopsy

tx: chemo & local resection

adamantinoma

90% found in tibia, usually diaphyseal, unknown cause, extremely slow growing, may metastasize to regional lymph nodes and lung, treated with wide resection

XR: benign tumor with a lytic central core that is surrounded by reactive sclerotic bone that typically bulges the anterior cortex and thus takes on the appearance of either fibrous dysplasia or osteofibrous dysplasia

chondrosarcoma

low grade malignant tumor, M>F age 30-60, minimal pain over several years, common in pelvis and femur, treated with aggressive surgical management, good prognosis

ewing sarcoma

MC in patients 5-25 years, pelvis is MC location (also femur, tibia, humerus, scapula), can masquerade as osteomyelitis, aggressive with high rate of recurrence and metastasis, treated with resection and multidrug chemo

XR: central lytic tumor of diaphyseal-metaphyseal bone, extensive permeative destruction of cortical bone, onion skin, reactive hair-on-end appearance