Embolic cerebellar infarction caused by spontaneous dissection of the extracranial vertebral artery--two case reports.

Spontaneous dissection of the extracranial vertebral artery (VA) may cause ischemic stroke in the posterior circulation. A 22-year-old female and a 38-year-old male presented with sudden onset of vertigo and nausea without trauma. Angiography was initially interpreted as normal, but retrospective examination disclosed extracranial VA dissection in the V3 segment in both cases. Arterial dissection resulting in embolic stroke in the territory of the ipsilateral posterior inferior cerebellar artery was highly suspected. Both patients were treated conservatively without sequelae. Careful angiographic interpretation is important for the diagnosis of extracranial VA dissection. Spontaneous extracranial VA dissection should be suspected in young patients presenting with ischemic stroke but without predisposing risk factors or associated trauma.