Spontaneous acute subdural hematoma complicating arachnoid cyst.

The overwhelming majority of cases of acute subdural hematoma in the forensic setting occur as a result of head trauma. We report a case of sudden unexpected death in a middle-aged woman with a history of arachnoid cyst who had sudden spontaneous onset of severe headache that was rapidly followed by collapse and death. A postmortem multiple-slice computed tomographic scan showed a large acute subdural hematoma associated with hemorrhage into an arachnoid cyst. Subdural hemorrhage is an uncommon but well-described complication of an arachnoid cyst.