[Focal myositis]

Focal myositis is a rare benign pseudotumor of skeletal muscle, of unknown cause. Clinically it presents as an enlarging mass within a muscle, usually in en extremity. Biopsy shows characteristic histological changes of inflammation, focal degeneration and regeneration. The natural course of this disorder is spontaneous regression. This report describes the case of a 17-year-old boy with focal myositis of the thigh and a review of the relevant literature.