Peripheral osteoma arising from the lateral surface of the mandibular ramus

Abstract

Osteomas are benign, slow-growing osteogenic tumors that consist of compact or cancellous bone. They sometimes arise from the craniomaxillofacial region. Among the peripheral, central, and extraskeletal types, peripheral osteomas arise from the periosteum, usually as unilateral, pedunculated, mushroom-like masses. Here, we report an unusual peripheral osteoma arising from the lateral surface of the mandibular ramus. A 57-year-old woman with a mass at the left mandibular ramus was referred to us. The hard and immobile mass had been growing for 15 years, and she had facial asymmetry. She had no trismus, temporomandibular joint dysfunction, previous facial trauma, or infection. Computed tomography showed a mushroom-like lesion (21.1 × 13.4 × 13.1 mm) arising from the lateral surface of the left mandibular ramus. Clinical diagnosis was peripheral osteoma. The lesion was removed using rotary instruments and a chisel through an intraoral approach under general anesthesia. The lesion had intruded into the masseter muscle. Pathological diagnosis was compact osteoma. The postoperative course was uneventful and there has been no recurrence 1.5 years after surgery.