An atypical case of adult Moyamoya disease with initial onset of brain stem ischemia.

We present an atypical case of adult moyamoya disease whose clinical onset consisted of ischemic symptoms of the brain stem. She initially presented with left hemisensory disturbance caused by a pontine lesion, followed by a myelopathy of the upper cervical spinal cord. Eight months later, she presented with left hemiplegia and disturbed consciousness. Magnetic resonance angiography showed significant narrowing of both horizontal portions of the middle cerebral arteries (M1). Conventional angiography revealed bilateral occlusion of the internal carotid arteries. Her anterior circulation was supplied from the vertebro-basilar system through Moyamoya vessels and leptomeningeal collaterals. The intracranial steal phenomenon was thought to be the reason for the preceding events in the brain stem and upper cervical spinal cord. In addition, transcranial color-coded duplex sonography (TCCS) showed identical findings to conventional angiography with antegrade flow in the proximal M1 and retrograde flow in the distal M1. Thus, TCCS was useful for diagnosing the M1 occlusion in this case of Moyamoya disease.