Iatrogenic cerebral amyloid angiopathy: a scoping review

Published cases of iatrogenic cerebral amyloid angiopathy (iCAA) are increasing; however, their geographic distribution and age-related clinical spectrum have not been systematically characterised. We aimed to characterise the published evidence, including Japan's contribution and differences in presentation by age.

A scoping review of published iCAA cases was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA). We searched MEDLINE, Scopus and Ichushi-Web-a major Japanese medical literature database-from database inception to 31 January 2026. Reports were screened using broad clinical and exposure compatibility criteria, and included cases were retrospectively classified according to the revised Queen Square framework. We summarised the global distribution and clinical profiles of published cases; comparisons of cases reported from Japan versus other countries and onset before versus at or after 55 years were exploratory.

57 reports describing 94 cases were included. Japan contributed the largest number of published cases although case counts cannot estimate incidence. The median age at first presentation and first exposure was 42 and 4 years, respectively; the median latency was 36 years. Cranial surgery was the main exposure event, with cadaveric dura mater identified in 44 cases. Acute intracerebral haemorrhage (ICH) was the first presentation in 58 cases. Among cases with older onset (≥55 years), acute ICH was less frequent at presentation.

Published iCAA cases were most frequently reported from Japan; however, ascertainment and publication biases preclude geographic incidence comparisons. iCAA may present after age 55 and without acute ICH, supporting systematic exposure-history ascertainment and internationally coordinated registry-based surveillance.