Primary clival mucocele: case report.

A 40-year-old man presented with a history of diplopia due to left abducens nerve palsy persisting for a few days. Neuroimaging examinations revealed a cystic mass in the clivus and erosion of its posterior wall. Drainage of the lesion was accomplished through a small bone defect in the anterior wall of the clivus using the endoscopic endonasal transsphenoidal approach. This procedure improved the symptoms of the patient. Intraoperative and histological findings led to a diagnosis of mucocele. A mucocele localized only in the clivus is uncommon and the pathogenesis may be closely related to pneumatization of the clivus.