Dramatic disappearance of moyamoya disease-induced chorea after indirect bypass surgery.

A 31-year-old woman with moyamoya disease presented with choreiform movements persisting for 4.5 years. Magnetic resonance imaging showed a fine vascular plexus in the base of the brain but no parenchymal brain damage. Cerebral angiography revealed intracranial vascular abnormalities compatible with moyamoya disease. Single photon emission computed tomography with N-isopropyl-p-(123)I-iodoamphetamine showed definite reduction of the regional cerebral blood flow (rCBF) in the bilateral striata and frontotemporoparietal cortex. rCBF study with acetazolamide administration indicated marked decrease of rCBF reserve in those regions. She underwent indirect bypass surgery (encephalo-duro-arterio-myo-synangiosis) under a diagnosis of moyamoya disease. The choreic involuntary movements disappeared shortly after surgery. Postoperative angiography showed neovascularization in the extracranial to intracranial direction, associated with dramatic increase in rCBF in the involved regions.