Extradural dermoid cyst located in the lateral sphenoid ridge.

Dermoid cysts are rare congenital tumors that occur primarily at the midline at a characteristic intradural location. However, dermoid cysts located at extradural and lateral regions have been rarely reported until now. In the present study, the authors demonstrate the unusual instance of an intracranial extradural dermoid cyst at the lateral sphenoid ridge. A 53-year-old woman admitted because of progressive headache and dizziness. The patient had no neurologic deficits, and magnetic resonance imaging with no contrast enhancement revealed a mass at the right sphenoid ridge. The mass was accompanied with sphenoid bone erosion visible on computed tomography. The patient underwent right pterional craniotomy, and the tumor including the capsule was totally resected. Presence of a dermoid cyst was confirmed with histopathological examination. The patient had no complications during the postoperative period. This study suggests that dermoid cyst should be considered for differential diagnosis of extradural and lateral intracranial masses.