[Angiographically visualized extravasation in a case of arteriovenous malformation: the first case in Japan (author's transl)].

A case of arteriovenous malformation (AVM) with angiographically visualized extravasation of contrast medium on carotid angiography has been reported. The patient, a 9-year-old girl, came to our clinic with chief complaints of unconsciousness and left hemiplegia. On right carotid angiogram, done 4 hours after stroke, an AVM with a large intracerebral hematoma at the region of the right basal ganglia was recognized. The AVM was feeded from several lenticulostriate arteries and a small branch from precentral artery, and drained into thalamostriate vein. The extravasation of contrast medium was seen in a sash like fashion through arterial and venous phase. Extravasation of contrast medium from AVM has been extremely rarely reported, and this is considered as the third reported case. From the study of these 3 cases, we have discussed about the rarity of the extravasation from AVM and the causative factors.