Rapid development of giant fusiform cerebral aneurysms in angiographically normal vessels.

Several reports have mentioned formation of new saccular aneurysms in previously normal-appearing vessels, but de novo fusiform aneurysms have not been reported. We describe three children who initially presented with giant fusiform aneurysms involving the cervical and petrous portions of the internal carotid artery and were treated with balloon occlusion. Between 2 and 6 years later, they were found to have new giant fusiform aneurysms in the vertebrobasilar system.