A case of bilateral mandibular osteoma of atypical form

Abstract

An osteoma is a benign osteogenic tumor arising from the proliferation of mature bone. They have been reported to occur primarily in the mandible in the oral and maxillofacial region. No previous report has described a large bilateral osteoma with wing-like form arising from the mandibular ramus. We report herein a case of bilateral osteoma of atypical form occurring in the mandible. A girl of 15 years of age presented with the chief complaint of swelling and food impaction in the left side of the oral floor. Computer tomography revealed a bone-like structure extending from the inside surface of the left side mandible to the ipsilateral oral floor. In addition, another bone-like mass was shown inside the right side mandibular ramus. Both structures presented wing-like characteristic forms. A clinical diagnosis of bilateral osteoma of the mandible was made, and we performed extirpation of the tumor from both sides under general anesthesia. Pathological findings showed that the left side mass was comprised of compacted bone alone and the right side mass contained both compacted bone and cancellous bone. In conjunction with imaging tests, the masses were both diagnosed as osteoma. In the 12 months following the surgery, there has been no recurrence in the left side, whereas a new bone formation was recognized in the right side surgical site.