A noncancerous bone tumour, which is formed from a stalk of bone capped with cartilage, and appears as a hard round swelling near a joint. An osteochondroma develops in late childhood and early adolescence, usually from the side of a long bone near the knee or shoulder. The tumour causes problems only if it interferes with movement of tendons or the surrounding joint, in which case it may be removed surgically. Large osteochondromas can interfere with skeletal growth, causing deformity.
a bony protuberance covered by a cap of cartilage arising usually from the end of a long bone, most commonly around the knee or shoulder. It is due to overgrowth of cartilage at the edge of the *physis (growth plate) of growing bones. The protuberance may be flattened (sessile) or stalklike (see exostosis) and usually appears before the age of 30, with patients complaining of either pain or a lump. There is a small incidence (1–2% in solitary lesions, higher if multiple) of malignant transformation of the cartilage cap into a *chondrosarcoma. If the lump causes symptoms or continues to grow in an adult, it should be excised.
n. a benign outgrowth of bone with a cap of cartilage, arising from a bony surface. It is a stalklike *osteochondroma. Hereditary multiple exostoses (diaphyseal aclasia, familial osteochondroma) is a hereditary (autosomal *dominant) abnormality of cartilage and bone growth that results in the formation of multiple exostoses, most commonly at the ends of the long bones.... exostosis
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