Subdural and intracerebral hemorrhage caused by spontaneous bleeding in the middle meningeal artery after coil embolization of a cerebral aneurysm.

Nontraumatic acute subdural hemorrhage (SDH) with intracerebral hemorrhage (ICH) is rare and is usually caused by severe bleeding from aneurysms or arteriovenous fistulas. We encountered a very rare case of spontaneous bleeding from the middle meningeal artery (MMA), which caused hemorrhage in the temporal lobe and subdural space 2 weeks after coil embolization of an ipsilateral, unruptured internal cerebral artery aneurysm in the cavernous portion. At onset, the distribution of hematoma on a computed tomography scan led us to believe that the treated intracavernous aneurysm could bleed into the intradural space. Emergency craniotomy revealed that the dura of the middle fossa was intact except for the point at the foramen spinosum where the exposed MMA was bleeding. Retrospectively, angiography just before and after embolization of the aneurysm did not show any aberrations in the MMA. Although the MMA usually courses on the outer surface of the dura and is unlikely to rupture without an external force, physicians should be aware that the MMA may bleed spontaneously and cause SDH and ICH.