Ectopic sphenoid sinus meningioma with huge hyperostosis: a rare case report and review of literature

Meningioma is a slow-growing and generally benign neoplasms occurring in the intracranial region, however, ectopic meningioma originating in sphenoid sinus (SS) are exceedingly rare. We reported a 49-year-old male of ectopic SS meningioma. This case is, to the best of our knowledge, the fourth case report of ectopic SS meningioma and the first case with huge hyperostosis in this location. The patient presented with 4-month history of dizziness and progressive blurred vision of right eye. Imaging studies showed a mass in the SS invading into posterior ethmoid sinuses, optic canal and cavernous sinus. There was a marked hyperostosis in the inferior wall of ethmoid sinuses. The tumor was almost completely removed via the endonasal endoscopic approach under navigation system, and the patient subsequently underwent stereotactic radiotherapy to control the tumor remnant. Pathological and Immunohistochemical examination established a transitional meningioma (Grade I WHO). No relapse was found at 5-year follow-up. Ectopic SS meningioma exhibits nonspecific symptoms, so the accurate diagnosis rests on the histological and immunohistochemical examinations. Total removal via the endonasal endoscopic approach is the treatment of choice for ectopic SS meningioma, with subsequent radiotherapy to help control any residual tumor.