Myositis ossificans occupying the thenar region: a case report

Myositis ossificans is a benign, self-limiting, tumor-like lesion that usually affects the elbow and thigh; occurrence in the hand is uncommon. We report a rare case of a patient with myositis ossificans in the thenar region.

A 15-year-old Japanese girl presented to our hospital with a 2-month history of a painful mass in the right thenar region without previous trauma. The clinical and radiological examination findings suggested an osteoblastic malignancy. A diagnosis of myositis ossificans was made on the basis of an incisional biopsy. Despite the location of the lesion in the thenar region, a normal functional outcome was achieved after marginal resection of the mature lesion.

Clinicians should consider myositis ossificans as a possible diagnosis for a soft tissue mass in the hand, thereby avoiding unnecessarily aggressive therapy.