Posterior inferior cerebellar artery aneurysm displaying some atypical findings

Report of a case and review of the literature

Abstract

We encountered a case of peripheral posterior inferior cerebellar artery aneurysm. A 79-year-old female was admitted to our institute because of sudden onset of severe headache. An examination (angiography) revealed a succular aneurysm of the right vertebral artery which terminated at the right posterior inferior cere-bellar artery. The ruptured aneurysm at the corner between the lateral medullary segment and posterior medullary segment of the posterior inferior cerebellar artery was successfully clipped ; however, there was no branch take-off at around the origin of the aneurysm. Previously another unruptured aneurysm had been noted at the right internal carotid terminus as a multiple aneurysm. From these findings, it is suggested that congenital factors could have been as important in the etiology (pathogenesis) of the aneurysm as an increase in hemodynamic stress. We discuss this problem together with other reported cases.