An Isolated Laminar Osteoma Arising in the Maxillary Sinus

BACKGROUND Osteomas are benign tumors characterized by proliferation of dense or trabecular bone. Most osteomas of the head and neck occur in the mandible, they rarely occur in the maxillary sinus, and free osteomas are extremely rare. While usually detected incidentally on plain radiographs, symptoms appear when the osteoma obstructs the sinus orifice or invades the adjacent orbit or intracranial structures. Herein, we report a case of a patient with an isolated laminar osteoma arising in the maxillary sinus. CASE REPORT A 52-year-old man presented to our hospital with a radiopaque mass in the right maxillary sinus. An oval mass of size 2.7×2.3 cm was observed in the right maxillary sinus on computed tomography, and no sinusitis was present. Under general anesthesia, the mass was removed orally via the modified Caldwell-Luc method. Histopathologic examination revealed layered compact bony tissue covered by the sinus membrane. The mass was free from the inferior wall of the right maxillary sinus, and a part of the mass was covered by the sinus membrane. The postoperative course was uneventful, and no recurrence was noted after 5 years. CONCLUSIONS We experienced a case of an extremely rare osteoma in the maxillary sinus. The osteoma was solitary and free within the maxillary sinus. The treatment performed was surgical excision using the modified Caldwell-Luc method. The cause of the free osteoma was thought to be odontogenic maxillary sinusitis caused by apical periodontitis of the nearby tooth.