Nontraumatic Convexal Subarachnoid Hemorrhage Accompanied by Sylvian Hematoma: An Autopsy Case of Ruptured Distal Middle Cerebral Artery Aneurysm.

We describe an autopsy case of nontraumatic convexal subarachnoid hemorrhage (cSAH) accompanied by sylvian hematoma. A woman in her 50s was found dead in her house. On autopsy, massive cSAH accompanied by sylvian hematoma was observed. Because of the absence of subarachnoid hemorrhage (SAH) in the basal cistern, initial suspicion was that of a traumatic SAH. After a detailed investigation, a ruptured cerebral aneurysm of the distal middle cerebral artery was found in the hematoma, and the cSAH in this case was confirmed to be endogenous. Convexal subarachnoid hemorrhages typically result from traumatic injury, whereas endogenous cSAHs are exceedingly rare. Autopsy findings of a sylvian hematoma with SAH may result from endogenous hemorrhage from ruptured aneurysm of the distal middle cerebral artery. Detailed investigation of the hematoma may help identify the culprit lesion and help arrive at the correct postmortem diagnosis.