[Wyburn-Mason syndrome--a case report].

A 5-year-old girl with Wyburn-Mason syndrome was reported. A vascular nevus on the right cheek was noticed since early infancy. External strabismus and impaired vision of the right eye were noticed at 5 years of age. Fluorescein angiography showed an arteriovenous malformation on the right retina. Brain CT, MR, and right carotid angiography demonstrated an arteriovenous malformation from the orbita to the hypothalamic region along the optic nerve. This congenital vascular disorder is extremely rare.