Middle cerebral artery main stem thrombosis in two siblings with familial thrombotic thrombocytopenic purpura.

Idiopathic thrombotic thrombocytopenic purpura (TTP) is frequently complicated by microinfarcts in cerebral cortex and subcortical white matter. We describe two sisters who suffered massive hemispheric infarction due to thrombosis of the middle cerebral artery main stem during exacerbations of TTP. Acute TTP may be associated with intraluminal thrombosis of large-diameter arteries in addition to arterioles and capillaries.