Abstract
We report a rare case of ruptured dissecting aneurysm of the right anterior cerebral artery A1 segment associated with multiple unruptured saccular aneurysms, including a left internal carotid aneurysm of the C2 segment, right middle cerebral artery aneurysm, and basilar bifurcation aneurysm. Initial computed tomography and magnetic resonance imaging performed 2 days after the onset failed to reveal subarachnoid clot, necessitating bilateral craniotomy to detect and treat the responsible lesion. All aneurysms were successfully occluded in a two-stage operation. Because of subtle angiographic findings, a dissecting aneurysm of the A1 segment may be overlooked as a cause of subarachnoid hemorrhage, especially in association with multiple saccular aneurysms. As it is sometimes difficult to detect a ruptured aneurysm among multiple cerebral aneurysms despite extensive neuroimaging, surgery is still necessary when a patient presents with subarachnoid hemorrhage.
