Heterotopic ossification in orbital roof, frontal sinus, and ethmoidal cells leading to hypoglobus and upward-gaze deficit.

Heterotopic ossification (HO) of facial sinuses is very rare. In this article, we present an extensive HO case covering the right frontal sinus, superior ethmoidal cells, and upper orbital rim and roof. This mass was leading to a hypoglobus and upward-gaze deficit due to mass effect. With an upper eyelid incision, mass over the upper orbital rim and roof was excised by an osteotome. Histopathologic examination was compatible with HO. On the postoperative 18-month follow-up, hypoglobus and upward-gaze deficit have significantly regressed. There were no relapses or enlargement over the operative field or the primary mass seen on computed tomography scans.