Spontaneous isolated posterior communicating artery dissection in a young adult with hyperhomocysteinemia.

A 28-year-old man presented with an acute spontaneous dissection of the left posterior communicating artery with associated ipsilateral thalamic and internal capsular infarctions. Positive risk factors included smoking and family history of ischemic heart disease. He was also found to have hyperhomocysteinemia, which has been implicated as a risk factor for spontaneous cervical artery dissection, but to date, no association has been shown with spontaneous intracranial arterial dissection.