Oculomotor palsy from an unruptured posterior communicating artery aneurysm presenting with cerebrospinal fluid pleocytosis and enhancement of the third cranial nerve. Case report.

The authors describe a patient with an unruptured posterior communicating artery aneurysm presenting with enhancement of the third cranial nerve on magnetic resonance (MR) imaging and cerebrospinal fluid (CSF) pleocytosis. Pathological entities associated with enhancement of the third cranial nerve on MR imaging are discussed and the authors speculate about the possible explanation for the CSF pleocytosis.