Progressive occlusive disease of large cerebral arteries and ischemic events in a patient with essential thrombocythemia.

We report a patient with essential thrombocythemia (ET) who developed progressive occlusive cerebrovascular disease accompanied by ischemic events. A 40-year-old woman presented with an ischemic stroke in the territory of the left middle cerebral artery (MCA). Diagnostic work-up disclosed a moderate stenosis of the left carotid siphon and a mildly increased platelet count. Due to aspirin intolerance warfarin was administered. Twelve months later, ischemic strokes in the left MCA territory recurred. A left internal carotid artery occlusion at the origin was diagnosed. Bone marrow biopsy showed an increased number of megakaryocytes. Warfarin was replaced by clopidogrel. Cerebral artery obstructions remained unchanged during the next 3 years (six follow-up examinations); no further ischemic events occurred during that period, while mild thrombocytosis persisted. ET may be associated with progressive obstructions of large cerebral arteries; in our case, clopidogrel was effective in preventing recurrence of ischemic events.