Cerebral amyloid-β-related angiitis without cerebral microbleeds in a patient with subarachnoid hemorrhage.

Amyloid-β-related angiitis (ABRA), a subtype of cerebral amyloid angiopathy (CAA), is vasculitis occurring in relation to amyloid-β (Aβ) deposition in the walls of intracranial blood vessels. ABRA is presumed to be caused by some immune response to the deposited Aβ. An 81-year-old man on oral anticoagulant therapy complained of headache, nausea, and difficulty with standing after a head injury. Head computed tomography revealed subcortical bleeding in the right temporoparietal lobe, and 3 days after admission, magnetic resonance imaging (MRI) showed subarachnoid hemorrhage (SAH) around the hematoma. Cerebral microbleeds, a characteristic of CAA, were not detected on MRI. On worsening of his symptoms, intracranial brain biopsy and hematoma removal were performed. Intraoperative rapid diagnosis with a frozen section suspected vasculitis, which enabled the prompt initiation of steroid therapy. He was pathologically diagnosed with ABRA (granulomatous angiitis) using a formalin-fixed paraffin-embedded section. Vasculitis was prominent around blood vessels in the pia matter covering the cerebrum. In this case, the inflammatory cells seemed to appear via the subarachnoid space following cerebral hemorrhage and SAH. ABRA seemed to be developed by intracranial hemorrhage in this case.