[A case of cerebral amyloid angiopathy in which a restricted subarachnoid hemorrhage recurred in the cortical sulcus following a subcortical hemorrhage].

Cerebral amyloid angiopathy (CAA) is predominantly recognized in elderly people and repeatedly causes a huge subcortical hemorrhage. Some cases of CAA can cause secondary subarachnoid hemorrhage (SAH), but cases in which it causes primary SAH is very rare. We describe a valuable reference case of a 75-year-old man in whom a restricted SAH recurred in the cortical sulcus following a huge subcortical hemorrhage. He presented with an unknown restricted SAH in the left frontal sulcus twice before neck clipping for a right IC-PC unruptured aneurysm. Postoperative computed tomography (CT) revealed a recurrent SAH in the left frontal lobe, and it spread gradually. T2(*) weighted imaging (T2(*)WI) revealed subarachnoid hemosiderosis and superficial cortical hemosiderosis in the frontal and parietal lobe. On the 21st postoperative day, he suddenly presented right hemiplegia and a huge subcortical hemorrhage was observed in the left frontal lobe on CT. Emergent removal of the hematoma was performed, but the patient had become bedridden. Pathological diagnosis of CAA was made. A recurrent restricted SAH in the frontal sulcus might have been a warning sign of a huge subcortical hemorrhage. In the aging society, a radiological prediction of CAA is very important. Although it is generally thought to be very difficult, T2(*)WI may be useful for predicting CAA. When we plan surgery for elderly people, we must always take CAA into consideration.