Best Post of November 2015: A 60-year-old woman with a left occipitotemporal brain lesion

The next in our "Best of the Month" series comes from November 18, 2015:

We were sent this case in consultation to rule out infiltrating neoplasm. The diagnosis is amyloid beta related angiitis (ABRA). In this case, no infarction was present in the specimen, but white matter rarefaction (the presumed pathologic correlate to the leukoaraiosis reported on imaging) is present.

Granulomatous vasculitis associated with pink hyaline material in vessel walls

The pink hyaline material is shown to be beta-amyloid by immunohistochemistry

White matter rarefaction (upper half of picture) correlating with leukoaraiosis seen on imaging