Dissecting aneurysms of the posterior inferior cerebellar artery.

The authors present three cases of dissecting aneurysms of the posterior inferior cerebellar artery (PICA). A literature search revealed only three previous cases. Analysis of these six cases showed a unique clinical picture. Three patients developed subarachnoid hemorrhage, and the other three had ischemia. All patients complained of occipital headache or neck pain, regardless of the initial symptoms. Heralding episodes were recorded in four cases. Angiography showed a characteristic fusiform dilatation of the PICA and a narrowing proximal to and distal to the lesion. Various surgical treatments were performed in five cases. Intraoperative observation showed a sausage-like swelling of the PICA or one of its branches with various discoloration depending on the age of the intramural clot. The outcomes were favorable.