Extradural dermoid cyst of the parasellar region: a case report

Dermoid cysts are rare congenital intracranial tumors. Among these tumors, extradural localization is extremely rare. We report a patient with an extradural dermoid cyst of the right parasellar region, causing right visual disturbance. Computed tomography revealed a hypodense mass lesion with rimlike calcification at the right parasellar region, accompanying marked erosion of the adjacent skull base. The tumor appeared as a heterogeneous intensity on magnetic resonance imaging and was surrounded by thin gadolinium enhancement without inner enhancement. The right optic nerve was compressed by the tumor. Surgical resection was successfully performed using a right frontotemporal extradural approach. The entire tumor was completely resided extradurally and was enclosed by saclike, stretched dura mater and extended deeply into the skull base. Histopathologic findings were consistent with the features of dermoid cyst. The postoperative course was uneventful, and the visual disturbance improved. Neuroradiological features, strategies for surgical treatment, and mechanisms responsible for preoperative symptoms are discussed.