[A case of hemichorea caused by right internal carotid artery stenosis].

This is a case of a 71 years old man. Hemichorea appeared in the left half of his body in the middle of November, 2014. Minute hyperintense areas in the white matter near the posterior horn of the right lateral ventricle and in the right parasagittal frontal cortex was shown in MRI diffusion weighted image. Severe stenosis was seen in the right internal carotid artery, and reduction in cerebral blood flow of the right cerebral hemisphere including the basal ganglia was shown in single photon emission computed tomography (SPECT). After having carotid endarterectomy of the right internal carotid artery in January, 2015, hemichorea disappeared, and the cerebral blood flow of the right cerebral hemisphere improved. It is known that hemichorea is caused by the infarction of the basal ganglia. In recent years, some hemichorea cases are reported around East Asia caused by internal carotid artery stenosis with reduction in cerebral blood flow.