A benign bone tumour, of which there are two types. An osteoid osteoma most commonly occurs in the shaft of the femur or tibia. It is small, solitary, and relatively common; its characteristic feature is that it causes nocturnal pain that is relieved by aspirin. Treatment is by surgical excision. A compact osteoma (ivory exostosis) is a slow-growing tumour-like mass that usually causes no symptoms. Such tumours are relatively uncommon, occurring usually in the skull and facial bones. If they do cause symptoms, usually from local compression, they may be excised.
Subjects: Medicine and Health.