Pearls & Oy-sters: Arterial Wall Enhancements and Rapid Clinical Progression in Noninflammatory Cerebral Amyloid Angiopathy.

Cerebral amyloid angiopathy (CAA) is a common cause of lobar intracerebral hemorrhage (ICH) and cognitive impairment for which diagnostic criteria have been recently revised. A subset of CAA cases have superimposed inflammation in the form of CAA-related inflammation, which may result in a more severe clinical course. We present the case of a 61-year-old man who presented with subacute behavioral changes, motor aphasia, and right hemiparesis due to an ICH in the left superior frontal gyrus. Brain MRI revealed a small chronic cortico-subcortical right occipital hemorrhage and multiple lobar microbleeds, fulfilling the criteria for probable CAA. One year later, he developed acute psychosis with aggressive behavior. β-Amyloid (Aβ) 1-40 and 1-42 levels were reduced in the CSF, with normal total tau and phosphorylated tau. He remained clinically stable during the following years. At age 68, he showed a rapid cognitive deterioration over 6 months, atypical for CAA. Repeat brain MRI showed multiple cortico-subcortical microbleeds and microinfarctions. High-resolution vessel wall MRI showed concentric wall enhancement in multiple arterial segments. These findings raised concerns for an inflammatory process, in the form of either inflammatory CAA or vasculitis. The neuropathologic findings were consistent with severe CAA without vessel wall inflammation. This case highlights the periods of steep progression that may occur in CAA and that Aβ accumulation alone, without inflammation, may be associated with arterial wall enhancement, mimicking a vasculitic or amyloid-related inflammatory process. The value of this neuroimaging feature for patient stratification or prognosis requires further validation.