Nontraumatic myositis ossificans with an unusual location: case report.

Myositis ossificans is a pathologic entity rarely met, but still it must be kept in mind in differential diagnosis of a tender soft tissue swelling. The authors present an 8-year old boy with nontraumatic myositis ossificans circumscripta in the left paravertebral muscle. In diagnostic workup, ultrasonography and computed tomography (CT)-scan showed a well marginated, regular, ossified mass in the paravertebral muscle, but we were not able to exclude malignancy on the clinical grounds. The mass was excised totally, and the histopathologic examination found myositis ossificans. The authors suggest that surgical intervention may be an option for diagnosis and treatment in unusual cases when diagnosis is not certain.