[Amyloid β related angitis without marked leukoencephalopathy].

An 86-year-old woman was admitted to our hospital with headache and acute detarioration of consciousness. Cerebral microbleeds (CMBs) dominated the occipital lobe on the head MRI, revealing white matter lesions. It was accompanied by gadolinium (Gd) imaging effect in the leptomeninges and some CMBs. She was clinically diagnosed with amyloid β-related vasculitis and a good outcome was obtained with steroid therapy. Even when symptoms re-exacerbated, exacerbation of the contrast effect of CMBs was observed, but no white matter lesions appeared, and leptomeningeal enhancement did not change remarkably throughout the entire course.