[Diagnosis and spontaneous course of non-traumatic localized myositis ossificans]

Non-traumatic localized myositis ossificans is a rare variant of pseudotumoral muscular ossification. In the early stage it may be misdiagnosed as soft tissue sarcoma or some kind of osteosarcoma. Myositis ossificans itself does not always require therapy; when diagnosed on the basis of the typical features revealed by meticulous non-invasive investigation, biopsy is not mandatory for confirmation of the diagnosis. The diagnostic procedures needed - radiography, ultrasound, MRI, and isotope bone scan - are discussed with reference to three clinical case reports.