Cerebral amyloid angiopathy with atypical imagingfindings of subarachnoid hemorrhage.

Cerebral amyloid angiopathy (CAA) is observed in most cases of nonhypertensive subcortical hemorrhage involving elderly patients. We herein describe the case of a female in whom a convexal subarachnoid hemorrhage was observed at 55 years of age. The cerebral hemorrhage occurred repeatedly; however, no obvious vascular lesions were observed on a cerebral angiography, and no signs of microbleeding or lesions in the deep white matter were identified on magnetic resonance imaging (MRI). Partial excision of the right frontal cortex and hematoma evacuation were performed, and histopathological examination showed deposition of an acidophilic substance with positive staining for Direct Fast Scarlet (DFS) in the cerebral vascular wall. Finally, brain hemorrhage due to CAA was diagnosed. This case suggests that CAA is an important differential diagnosis in patients with localized non-aneurysmal subarachnoid hemorrhage in the convexity sulcus.