Bone Tumors Flashcards
Key radiologic features
Bones involved, location, lytic vs sclerotic, tumor margin/zone of transition, matrix formation, periosteal reaction, soft tissue involvement
Cartilage/chondroid producing tumors
Endochondroma, osteochondroma, chondrosarcoma, chondroblastoma, chondromyxoid fibroma
Bone producing tumors
Osteoid osteoma/osteoblastoma, osteosarcoma
No matrix/unknown cell type
Giant cell tumor of bone, non-ossifying fibroma, Ewing sarcoma, aneurysmal bone cyst, fibrous dysplasia
Enchondroma definition
Benign tumor of hyaline cartilage
Enchondroma age and sex
20-50 years old, males and females equally affected
Enchondroma common locations
Metaphysis of long bones, tubular bones of hands and feet
Enchondroma gross appearance
Lobules of cartilage in medullary cavity
Enchondroma histologic features
Circumscribed lobules of cartilage with low cellularity
Enchondroma syndromes
Ollier’s disease and Maffucci syndrome
Osteochondroma definition
Benign mixed tumor
Osteochondroma age and sex
10-30 years, males and females equally affected
Osteochondroma locations
Long bone metaphysis
Osteochondroma gross appearance
Mushroom shaped growth at metaphysis
Osteochondroma histologic features
Cartilage cap with underlying bone and marrow in stalk, cap points away from joint
Osteochondroma syndromes
Multiple hereditary exostosis (MHE)
Chondrosarcoma definition
Malignant sarcoma that forms cartilage
Chondrosarcoma age and sex
50-70 years, unless associated with syndrome, males and females equally affected
Chondrosarcoma locations
Axial skeleton more often than appendicular skeleton
Chondrosarcoma gross appearance
Can look like enchondroma but often shows destruction of cortex and soft tissue invasion
Chondrosarcoma histologic features
Lobules of more cellular cartilage that entrap host trabecular bone and destroy cortex
Chondrosarcoma syndromes
Ollier’s disease, Maffucci syndrome, multiple hereditary exostosis (MHE), the most common sarcoma in Paget’s disease
Osteoid osteoma/osteoblastoma definition
Circumscribed benign bone tumors
Osteoid osteoma/osteoblastoma age and sex
10-20 years, males more often affected than females
Osteoid osteoma/osteoblastoma locations
Osteoid osteoma - metaphysis of long bone
Osteoblastoma - spine
Osteoid osteoma/osteoblastoma gross appearance
Central lucent area surrounded by abundant new bone
Osteoid osteoma/osteoblastoma histologic features
Central lytic bone forming area with reactive surrounding sclerosis
Osteoid osteoma/osteoblastoma syndromes
None
Osteosarcoma definition
Malignant bone forming sarcoma
Osteosarcoma age and sex
Bimodal age, but most are younger than 20 years old, males are affected more than females
Osteosarcoma locations
Metaphysis of long bones, especially of knee
Osteosarcoma gross appearance
Destructive tumor with bone with or without cartilaginous area
Osteosarcoma histologic features
Malignant osteoblasts form immature tumor bone
Osteosarcoma syndromes
Hereditary retinoblastoma, Li-Fraumeni, others
Giant cell tumor of bone definition
Benign in almost all cases but has aggressive local destructive growth, non-aggressive “metastases”
Giant cell tumor of bone age and sex
Adults, 20-40 years old (epiphysis closed), males and females equally affected
Giant cell tumor of bone locations
Epiphysis (can invade into metaphysis and diaphysis) of long bones, distal radius, pelvis
Giant cell tumor gross appearance
Large lesion located in the epiphysis of bone, sometimes surrounded by smaller, similar looking lesions
Giant cell tumor of bone histologic features
Numerous osteoclasts evenly distributed in a background of plump spindle cells, osteoclasts (multinucleated giant cells) are reactive, osteoblast progenitor cells are neoplastic (express high levels of RANKL)
Giant cell tumor of bone syndromes
None
Ewing sarcoma definition
Malignant, high grade sarcoma
Ewing sarcoma age and sex
Most under the age of 20, males affected more often than females
Ewing sarcoma locations
Diaphysis of long bones and pelvic bones
Ewing sarcoma gross appearance
“Onion skin” appearance of bone
Ewing sarcoma histologic features
Small round blue cell tumor (undifferentiated blastic appearing cells), often shows membranous reactivity for CD99 (MYC) in immunohistochemistry
Ewing sarcoma syndromes
None
Fibrous dysplasia definition
Benign bone lesion that some consider a localized developmental arrest
Fibrous dysplasia age and sex
Adolescence (before epiphysis closes), males and females equally affected
Fibrous dysplasia locations
Knee, ribs, skull, gnathic, humerus, pelvic bones (pelvis in polyostotic only), can be any bone
Fibrous dysplasia gross appearance
The normal components of bone are present, but do not differentiate into mature structures
Fibrous dysplasia histologic features
Circumscribed intramedullary nodule of “Chinese character” or alphabet soup of woven bone spicules set in a fibrous matrix, cartilage present in 20% of cases
Fibrous dysplasia syndromes
Polyostotic (one side of the body), Mazabraud syndrome, McCune-Albright syndrome
Effects of metastases to bone
Pathologic fractures, factors released locally by tumors (such as RANKL) lead to lytic lesions or other factors that lead to increased reactive density (sclerotic lesions), bone pain, osteoporosis (tumor-induced), hypercalcemia
Osteosarcoma mutations
CDKN2A, Rb1, p53, MDM2 CDK4
Ewing sarcoma mutations
FLI-1-EWS or ERG-EWS, t(11;22), t(21;22)
Chondrosarcoma mutations
EXT1 or EXT2 (with MHE), IDH1 or IDH2 (with Ollier’s/Maffucci), CDKN2A
Osteochondroma mutations
EXT1 or EXT2
Osteoid osteoma/osteoblastoma mutations
Unknown
Enchondroma mutations
IDH1 or IDH2
Giant cell tumor of bone mutations
H3F3A
Fibrous dysplasia mutations
GNAS1
