[A case of neuro-Behçet's disease presenting with chorea].

A 46-year-old man was admitted to our hospital because of emotional instability and involuntary movement of the right upper limb. Neurological examination revealed inability to concentrate, emotional incontinence, recent memory disturbance, chorea of bilateral upper limbs and neck, and bilateral pyramidal signs. Brain MRI showed atrophy of bilateral caudate nucleus and diffuse abnormal intensity area with low intensity on T1-weighted images and high intensity on T2-weighted images in cerebral white matter around the lateral ventricles. Huntington's disease was suspected at first, but it was ruled out by DNA analysis. After admission, oral and genital aphthae developed and the CSF examination showed pleocytosis (273 leukocytes/mm3; 39 polymorphonuclear leukocytes and 234 lymphocytes), so we diagnosed this case as neuro-Behçet's disease. Although basal ganglia is occasionally involved in neuro-Behçet's disease, chorea is rare. Neuro-Behçet's disease should be considered as a cause of chorea.