Proximal M2 false aneurysm after head trauma--Case report.

A 72-year-old male presented with a post-traumatic false aneurysm of the right proximal M2 artery with massive subarachnoid hemorrhage after closed head injury. Serial computed tomography (CT) and angiography showed the development of the aneurysm which was verified at autopsy. He was admitted in a drowsy state just after a motorcycle accident. Initial brain CT showed subarachnoid hemorrhage without skull fracture. Follow-up brain CT showed a huge hematoma in the right temporal lobe. He died 47 hours after the accident. Histological examination of the aneurysm showed a false aneurysm. Delayed diagnosis of traumatic aneurysms leads to high mortality, so early surgical treatment is essential to save such patients.