Solitary compact osteoma of the inferior border of the mandible protruded into the anterior belly of the digastric muscle. Issue 4 (July 2018) - Ito, Ko
Abstract: Osteomas are uncommon, benign, slow-growing osteogenic tumors, arising from the bones, can be classified as central, peripheral, or extra-skeletal. Peripheral osteomas develop as masses attached to the cortical bone, and are mushroom-shaped masses protruding from the periphery of the jaw bones. Here we report an unusual solitary compact osteoma arising from the inferior border of the mandible but predominantly in the anterior belly of the digastric muscle. A 58-year-old Japanese woman had a hard mass in the submental region. Computed tomography showed a hyperdense, well circumscribed mushroom-like lesion measuring 2.1 × 1.2 cm in size, and the lesion was located from the inferior border of the mandible in the left anterior belly of the digastric muscle. The clinical and radiological diagnosis was peripheral osteoma. The patient underwent resection of the osteoma through the submental skin incision under general anesthesia. Intraoperatively, the mass was present in the anterior belly of digastric muscle, and the tendinous origin of the muscle adhered to not to the mass but to the mandible. Histopathological examination showed a compact osteoma. The postoperative course was uneventful and there was no recurrence 5 years after surgery.