We report a case of probable cerebral amyloid angiopathy (CAA) presenting with almost 100 cerebral microhemorrhages in an apolipoprotein E 4 (APOE4) homozygous subject with mild cognitive impairment (MCI). CAA is highly prevalent in autopsy studies and may impact over 100 million individuals worldwide; however, it remains substantially underdiagnosed clinically. CAA raises the risk for intracerebral hemorrhages as well as amyloid-related imaging abnormalities (ARIA) with amyloid-targeted antibodies. CAA is especially a quandary in APOE4 homozygotes who are at greatest risk for both Alzheimer's disease (AD) and ARIA. This case highlights the urgent need for greater diagnostic awareness and therapeutic development.
Navarra et al. (2026) studied this question.