Focal myositis in the hand.

Focal myositis is a rare, benign, pseudotumor of skeletal muscle that is usually seen as a steadily enlarging soft tissue tumor in an otherwise healthy patient. Focal involvement of muscle with severe myopathic and inflammatory changes characterize the histology. The natural course of this disorder is spontaneous regression. We report the case of a 7-year-old girl with focal myositis of the index lumbrical muscle. This is the first reported incidence of focal myositis that involves muscle of the hand.