Unilateral moyamoya syndrome involving the ipsilateral anterior and posterior circulation associated with paroxysmal nocturnal hemoglobinuria.

Moyamoya refers to a phenomenon of stenoocclusive changes at or around the terminal part of the internal carotid artery (ICA). Moyamoya vessels develop in patients with (moyamoya syndrome) or without (moyamoya disease) various underlying diseases or conditions. Recent evidence shows that stenoocclusive lesions tend to involve the ipsilateral ICA system and posterior cerebral artery (PCA) predominantly in moyamoya disease. A 53-year-old Japanese woman with paroxysmal nocturnal hemoglobinuria presented with cerebral infarction from stenoocclusive involvement in the ipsilateral ICA and PCA associated with moyamoya vessels; she had no contralateral vascular lesion. Although predominant involvement of the ipsilateral ICA and PCA was associated with underlying disease (moyamoya syndrome) in the present case, it is a characteristic finding of moyamoya disease. We discuss the possible pathogenesis of the vascular changes of this case.