Tumoral calcinosis in an infant. A case report.

An unusual calcified soft tissue mass in the knee of an 18-month-old black male infant proved to be tumoral calcinosis. A relatively rare disorder of unknown etiology, this is one of the few reported cases of its occurrence in the knee. The diagnosis is one of exclusion. Because of their radiographic similarity, the differential diagnosis includes intracapsular and paraarticular chondroma, traumatic myositis ossificans, and calcinosis circumscripta.