[Coexistent congenital arteriovenous malformation an aneurysms of the scalp (author's transl)].

A rare case with coexistent extracranial congenital arteriovenous malformation and aneurysms of the occipital artery is presented. A 32-year-old man visited Tachikawa National Hospital with the complaints of occasional dizziness and a gradually growing pulsatile mass in the left occipital region. The patient had had no head trauma. Neurological examination revealed no abnormality. Physical examination showed a round and pulsating tumor measuring 4 cm x 7 cm in the retroauricular region on the left side, which lost its pulsation and consistency upon compressing the left common carotid artery. Left selective external carotid angiography demonstrated a tortuous and locally enlarged occipital artery with venous drainage around the artery and an arteriovenous malformation (AVM) in the retroauricular region and neck. The patient was successfully treated by surgical embolization of the feeding arteries with ligation of the left external carotid artery and partial excision of aneurysms under general endotracheal anesthesia. The postoperative course was uneventful. Fourteen months after the operation there is no evidence of recurrence of the pulsatile mass and the preoperative symptoms. Microscopic examination of the excised artery and aneurysms showed partial disappearance of the internal elastic lamina and muscle layer of the artery. Capillary nevi noted over the ear, retroauricular region, neck, and shoulder on the left side without history of head trauma and angiographic findings suggest that the AVM was congenital. In addition, we think that the aneurysms of the left occipital artery on the side ipsilateral to the AVM may have originated from the site of the arterial wall lacking the internal elastic lamina and developed due to hemodynamic mechanism associated with the AVM. Although the treatment of choice for extracranial, congenital and traumatic, AVMs is ideally total excision, careful embolization of the nidus with ligation of the feeders seems to be the most opportune procedure of choice as the second-best treatment in cases in which the nidus of the AVM occupies extensive areas of the head or face and which have little chance of developing serious signs and symptoms such as massive hemorrhage.