[Facial circumscribed ossifying myositis. Anatomo-clinical and tomodensitometric study]

1 case of circumscribed myositis ossificans of the temporal muscle is reported in a 21 years-old man. The initial complaint was a sudden non traumatic swelling. Roentgenography showed a characteristic feature: peripheral radio-opacity around a non-opacified area. Under microscope, we could find 3 zones: a central fibroblastic area, an intermediate zone with immature osteoid bone, a peripheral zone with mature lamellar bone. In addition, we used histoenzymological and electron microscopical methods. The difficulties of diagnosis, the pathogenesis and the prognosis of this disease were also discussed.