Atypical megadolichoectasia manifesting as brain infarction rapidly followed by fatal subarachnoid hemorrhage.

A 71-year-old female, without medical or family history for cerebrovascular disease, presented with basilar and bilateral carotid dolichoectasia manifesting as dysarthria and hemisensory disturbance, which resolved spontaneously within a day. She suffered brainstem infarction 28 months later, manifesting as drowsiness, dysarthria, and right hemiparesis. Her consciousness level progressively deteriorated to stupor within 4 days. Computed tomography taken on the 5th day confirmed cerebellar infarct in the perfusion area of the superior cerebellar artery but did not show subarachnoid hemorrhage. She died of acute respiratory failure on the 7th day. Autopsy demonstrated a tear in the lateral wall of the broad-based aneurysm on the ectatic basilar artery and diffuse subarachnoid hemorrhage. Vertebrobasilar ectasia is a dynamic vasculopathy that may rapidly progress in the affected basilar artery following an indolent clinical course. The prognosis for patients with vertebrobasilar ectasia may depend mainly on the pathological changes in the basilar artery.