Brief Report: Large Fusiform Aneurysm of a Circumflex Branch of the Posterior Cerebral Artery.

We report on a large fusiform aneurysm in a 20-year-old male with a history of cerebral palsy. Aneurysm location relative to four anatomical posterior cerebral artery segments dictates which approach should be used for treatment: pterional transsylvian, subtemporal, or parietooccipital interhemispheric transtentorial approach. A right temporal craniotomy via a subtemporal approach was performed and used to expose the right P1 and P2 segments of the posterior cerebral artery and the posterior communicating artery. Due to significant collateral circulation between the circumflex posterior cerebral artery and superior cerebellar artery branches, trapping of a fusiform aneurysm can be safely achieved without significant deficit.