[Spontaneous posterior sphenoid sinus fistula].
OBJECTIVE: Describe a rare localization of spontaneous cerebrospinal fistula. CASE REPORT: A 75-year-old women was admitted for bacterial meningitis arising from a sinus infection. She had not experienced facial or head trauma. The CT-scan revealed pneumocephaly and a defect in the posterior part of the sphenoid sinus. DISCUSSION: Spontaneous cerebrospinal fistula is uncommon. The exact etiology remains unknown.