Localized amyloidosis of seminal vesicles: report of three cases in surgically obtained material.

Localized amyloidosis of the seminal vesicles (ASV) is reported as an incidental finding in surgical specimens from three elderly men. In two cases, the amyloid deposits were bilateral, subepithelial, and clinically inapparent, features similar to other cases in the literature. In one case, the diagnosis was made on a transrectal prostatic needle biopsy that included a small portion of seminal vesicle; to our knowledge, this has not been previously reported. Electron microscopy in one case demonstrated nonbranching fibrils characteristic of amyloid, and pretreatment of tissue sections using the permanganate method in two cases showed almost complete ablation of congophilia. Evidence suggests that ASV is a permanganate-sensitive, non-AA (amyloid, protein A) type of amyloid that may be different from all other types of amyloid previously characterized.