Carotid artery dissections presenting as isolated posterior cerebral artery infarctions.

A spontaneous dissection of the carotid artery is a well-known cause of cerebral infarction, mostly due to an embolus from the affected vessel segment. For haemodynamic and anatomical reasons the territories of the middle and anterior cerebral arteries are usually involved. We report two cases of carotid artery dissections resulting in infarctions exclusively in the territory of the posterior cerebral artery. The underlying anatomical conditions were a fetal origin of the posterior cerebral artery and an embolic supra-ophthalmic occlusion of the internal carotid artery. To our knowledge similar cases have not previously been documented.