[A case of adult moyamoya disease showing fulminant clinical course associated with progression from unilateral to bilateral involvement].

We reported a case of adult moyamoya disease showing acute deterioration in which a unilateral occlusive lesion progressed to bilateral involvement during a period of 49 months. A 54-year-old male suffered from progressive weakness in his right extremities and disturbance of speech. On admission, neurological examination demonstrated mild right hemiparesis with global aphasia. A computed tomography (CT) scan showed a strange low density area in the territory of the left ACA and frontal branches of the left MCA. Left carotid angiography showed stenosis of the ICA at the terminal portion, occlusion of the ACA and MCA at each origin, and basal moyamoya vessels. Right carotid angiography demonstrated no occlusive lesions except for the general narrowing of the right ACA, without moyamoya vessels. This case was classified as adult-onset "probable" moyamoya disease according to the diagnostic criteria of the Japan Cooperative Research Committee. Left superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis was performed. The patient showed gradual amelioration of neurological symptoms, and was discharged on foot with mild motor aphasia. However, 4 years later he complained of weakness in his left lower extremity. A second cerebral angiography, performed 49 months after the initial angiography demonstrated severe stenosis of the left ICA at the terminal portion progressing in the proximal direction with decreasing basal moyamoya vessels, while severe stenosis extended from the terminal portion of the right ICA to the M1 portion with newly developed moyamoya vessels in the right basal area. At this time, we considered that this case was a definite case of moyamoya disease. The second cerebral angiography was completed uneventfully. However, the patient then suddenly showed acute deterioration 5 hours after the angiography. Emergent cerebral angiography disclosed an occlusion of the right ICA at the terminal portion. Thereafter he showed acute deterioration in consciousness. A CT scan at the time revealed a huge low density area in the territory of the right ACA and MCA. We performed emergent external decompression, but he did not recover from the sequelae of cerebral infarction and died 3 days later. This rare case suggested the possibility of progression to bilateral involvement although it was a case of adult-onset "probable" moyamoya disease. We consider that acute ischemic deterioration should be kept in mind especially in aged cases of adult-onset moyamoya disease. Careful observation should be performed by the serial MR angiography in adults with "probable" moyamoya disease even though they are clinically asymptomatic.