Sizeable Osteoma of Ethmoidal Labyrinth: Case Report

Background: Osteomas are benign, well-defined, and slow-growing tumors that consist mainly of mature compact or cancellous bone. The most common site in maxillofacial complex is the mandible, particularly the angle, followed by sinuses. Osteoma of the paranasal sinuses arises most commonly from the frontal sinus. The ethmoid and maxillary sinuses are less frequently involved.

Aim: The authors report a rare case of an osteoma of the left ethmoidal labyrinth, describing its clinical symptoms and radiographic findings, surgical treatment, and histological report.

Case Report: An 18-year-old man presented with periorbital swelling, complaining about orbital pain and epiphora of the left eye. The patient's medical history revealed recurrent episodes in the last 3 years, which were treated following the diagnosis of acute sinusitis. A three-dimensional computed tomography (CT) was performed to demonstrate a large lesion of osseous density of the left ethmoidal labyrinth (38 × 30 × 32 mm). Orthoptic examination revealed a noticeable diplopia, visual acuity impairment, and visual fields defects of the left eye. The intranasal surgical approach, with the use of microscope, and the Caldwell-Luc technique were combined to achieve the complete resection and removal of the lesion via the maxillary sinus. Due to its size, the attempt of its removal caused a fracture of the left orbital floor. In a second procedure, the orbital floor was reconstructed with a porous polyethylene (Medpor) implant. The histological report confirmed the clinical diagnosis of osteoma. The postoperative course was uncomplicated, and the lesion did not recur during a 4-year follow-up period. Repeated postoperative ophthalmic examinations revealed improvement of visual acuity and visual fields postoperatively.

Conclusions: Paranasal sinus osteomas are often asymptomatic. They are identified and treated at advanced stages because their symptoms mimic benign inflammatory conditions. In these cases, very careful preoperative evaluation and skillful operative maneuvers are considered to be essential.