[Peripheral arterial aneurysm of the brain occurring after brain abscess extirpation and healing spontaneously-report of a case and review of the literature (author's transl)].

In 33 year-old man an aneurysm of a pheripheral branch of the right middle cerebral artery was disclosed by angiography 8 days after extirpation of a parietotemporal brain abscess. The aneurysm was absent in the preoperative angiogram. Since the site of the aneutysm coincided with the operative field, it is sure that the etiology of the aneurysm was related to operative trauma and/or arteritis. Although inflammatory or mycotic factor could not be excluded from its etiology, it seems reasonable that traumatic factor was major one. The aneurysm was found to have disappeared eventually in the angiogram made on 372th postoperative day. Traumatic aneurysms arising from peripheral branches of the intracranial arteries are very rare. The first case was reported by Krauland in 1949. We collected 32 such cases from the literature. Of the 33 cases including the present one, 5 are iatrogenic. In more than half of the 33 cases, aneurysms were formed within 14 days following head injury. Posttraumatic delayed hemorrhage was found in 15 cases, the hemorrhage occurring within one month following injury in 12 cases. Of 31 cases with known prognosis, 11 died, 6 of them dying of delayed hemorrhage. Aneurysm operation was performed in 21 cases and 15 of them survived. In the present case, aneurysm luckily healed spontaneously. There are two cases including the present one, of spontaneous healing in the 33 cases. We believe surgical treatment is one of choice whenever possible.