RESUMO
Myositis ossificans circumscripta (MOC) is a rare benign condition characterized by heterotopic ossification occurring in the soft tissues. We report the case of a 15-year old patient complaining of mixed hip pain. No trauma has been reported during the interview. The joint had inflammation appearance and a non-mobilizing swelling adhered to the deeper structure with parietal projection over the groin fold. Radiographs of the hip showed a thickening of the soft tissues of the hip and some periarticular calcifications with unclear appearance. Excisional biopsy of the calcifications was decided and performed. Diagnosis was confirmed by histological examination of the surgical specimen. At six months follow-up the patient was very satisfied with his functional results. Returning to school sports was authorized. The patient had successful outcome.