P.189 Unruptured Posterior Cerebral Artery aneurysm causing temporal lobe epilepsy

Background: Cerebral aneurysms are an unusal cause of epilepsy. To date, several groups have reported temporal lobe seizures caused by aneurysms projecting into the parahippocampal gyrus. Given the low incidence of posterior cerebral artery aneurysms, they are a very rare cause of temporal lobe seizures. Methods: Here, we report a rare case of temporal lobe epilepsy caused by an unruptured aneurysm. We also present a review of the literature yielding two similar cases. Results: A previosuly well 56 year old male presented to a neurologist with symptoms consistent with temporal lobe epilepsy. He was started on carbamzepine and underwent imaging and neuropsychological assessments. An MRI suggested the existance of a 7mm posterior cerebral artery aneurysm arising from the P2 segment of the posterior cerebral artery and projecting into the parahippocampal gyrus. This was also confirmed with CT angiography and the patient elected to have the aneurysm clipped. Conclusions: Temporal lobe epilepsy is an uncommon presentation for unruptured cerebral aneurysms. We report a rare case wherein a laterally pointing PCA aneurysm was buried in the posterior parahippocampal gyrus. This aneurysm had caused perifocal gliosis leading to stereotyped seizures. Post-operatively, the patient has been seizure free.