Multiple cerebral infarcts with a few vasculitic lesions in the chronic stage of cerebral amyloid angiopathy‐related inflammation

We report a 75-year-old man with a 3.5-year history of cerebral amyloid angiopathy (CAA)-related inflammation. His initial symptom was headache and sensory aphasia appeared 1 month later. Brain MRI revealed features compatible with meningoencephalitis involving the right frontal, parietal and temporooccipital lobes. A brain biopsy sample from the right parietal lobe showed thickening of the leptomeninges, and granulomatous vasculitis with multinucleated giant cells and vascular Aβ deposits. No vascular lesions were evident by cerebral angiography. Serological examination revealed an elevated level of proteinase 3 anti-neutrophil cytoplasmic autoantibodies (PR3-ANCA). The patient was treated with corticosteroids, but this was only partially and temporarily effective. Autopsy revealed marked leptomeningeal thickening with inflammatory cell infiltrates and hemosiderin deposits, many superficial predominantly small infarcts at various stages in the cerebral cortex and only a few cerebral active vasculitic lesions. Immunohistochemically, CAA showing widespread Aβ-positive blood vessels with double-barrel formations was demonstrated. In conclusion, we consider that, although the association of PR3-ANCA with the pathogenesis of Aβ-associated vasculitis remained unclear, the present case represents a rare example of CAA-related inflammation at the chronic stage.