title: From the archives of the AFIP. Extraskeletal osseous and cartilaginous tumors of the extremities.
abstract: Extraskeletal osseous and cartilaginous tumors and tumorlike conditions of the extremities can often be differentiated radiologically; for those that cannot, knowledge of the spectrum of lesions will allow a suitably ordered differential diagnosis. Of the osseous lesions--myositis ossificans, fibro-osseous pseudotumor, fibrodysplasia ossificans progressiva, soft-tissue osteoma, and extraskeletal osteosarcoma--all but myositis ossificans are relatively rare. Myositis ossificans has a distinct mineralization pattern that can be observed radiologically as a peripheral rim of lamellar bone. Fibro-osseous pseudotumor typically occurs in the digits of the hand and lacks the well-defined zoning pattern of myositis ossificans. The cartilaginous entities include the true tumors, soft-tissue chondroma and extraskeletal chondrosarcoma, and the tumorlike process, synovial osteochondromatosis. The tumors are relatively rare; synovial osteochondromatosis commonly affects middle-aged men, especially in the knee, and is associated with osteoarthritis. The differential diagnosis for these extraskeletal osseous and cartilaginous lesions includes soft-tissue sarcoma, benign mesenchymoma, malignant mesenchymoma (rare), calcified tophi in gout, melorheostosis (rare), pilomatricoma (rare), and tumoral calcinosis (rare).
authors.affiliation: Department of Radiologic Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000.
authors.forename: M J
authors.initials: MJ
authors.lastname: Kransdorf
authors.forename: J M
authors.initials: JM
authors.lastname: Meis
mesh_terms: D000328:Adult; D000368:Aged; D002812:Chondroma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D015838:Chondromatosis, Synovial / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D005121:Extremities / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009221:Myositis Ossificans / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D009369:Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D010016:Osteoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D012516:Osteosarcoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed