[Tiny aneurysms of cortical arteries presenting as an acute subdural hematoma: a case report].

A case of an acute subdural hematoma due to the rupture of a tiny aneurysm of a cortical artery is described. A 68-year-old man lightly hit the right side of his head. About 1 hour later, he became drowsy and exhibited moderate hemiparesis on the left side on admission. Computed tomographic scanning demonstrated an acute subdural hematoma on the right temporoparietal region. In the past, he had undergone the clipping of a non-ruptured aneurysm and a subdural-peritoneal shunt operation on the same side in another hospital. On surgical evacuation of the subdural hematoma, a pulsating bleeding from a ruptured tiny aneurysm of a cortical artery was observed. There were also some similar tiny aneurysms on other cortical arteries. A photograph of such a tiny aneurysm was first taken and presented.