Dissecting aneurysm of the posterior inferior cerebellar artery: case report.

A patient with a dissecting aneurysm of a posterior inferior cerebellar artery who presented with Wallenberg's syndrome is reported. A 31-year-old man suddenly experienced an occipital headache, vertigo, and vomiting, followed by dysphagia. A neurological examination revealed partial Wallenberg's syndrome. Vertebral angiography revealed aneurysmal dilatation at the origin of the left posterior inferior cerebellar artery, with distal luminal narrowing. T1-weighted magnetic resonance imaging demonstrated an area of high-signal intensity, indicating an intramural hemorrhage in the arterial wall of the narrowed lumen. The dissecting aneurysm with a typical intramural hematoma of the posterior inferior cerebellar artery was entrapped with clips after an anastomosis of the left occipital artery to the distal posterior inferior cerebellar artery. The diagnosis and the treatment of dissecting aneurysms of the posterior inferior cerebellar artery are discussed.