Primary spontaneous CSF rhinorrhea through the clivus: possible etiopathology.

Primary spontaneous cerebrospinal fluid (CSF) rhinorrhea is rare. Only two such cases with a defect in the clivus have been previously reported in the world literature. The purpose of this report is not to discuss the operative approach or results but the etiopathogenesis of the defect at this very rare site. One patient had a defect in the posterior wall of the sphenoid sinus, just caudal to the dorsum sellae. In the other, a psuedomeningocele (thickened arachnoid outpouching) was found protruding into the sphenoid sinus through a defect in the middle of the clivus. Both cases were successfully managed with transsphenoidal surgery. Two additional cases of primary spontaneous CSF rhinorrhea through a defect in clivus are reported. The possible mechanism of the fistulae are discussed.