Bilateral tentorial subdural hematoma without subarachnoid hemorrhage secondary to anterior communicating artery aneurysm rupture: a case report and review of the literature.

A case of acute subdural hematoma over the tentorium secondary to rupture of an anterior communicating artery aneurysm is reported. A 42-year-old female patient presented with acute-onset, severe bifrontal and retro-orbital headache. CT revealed only symmetric thickening of the tentorium. MR imaging revealed the presence of a 10-mm anterior communicating artery aneurysm, which was confirmed by digital subtraction angiography. The radiologic findings and possible mechanisms of this hemorrhage are discussed.