We report a case of a carotid artery bifurcation aneurysm which ruptured into a silvian fissure arachnoid cyst. In the review of the literature, only three cases were before reported. We discuss about uncommom clinical findings, the surgical aspects and the associations among the lesions.
cerebral aneurysm; arachnoid cyst; subarachnoid hemorrhage; intracystic hemorrhage; pathogenesis