Inverted Urothelial Papilloma : Microscopic Features
Section Editor: Dharam M. Ramnani, MD
Virginia Urology, Richmond, VA, USA
Image Description
Microscopic Features: The cords, trabeculae and solid nests of inverted urothelial papillomas (IUPs) are composed of cytologically bland urothelial cells with minimal to no cytologic atypia. Some cases show focal degenerative-type atypia which is acceptable and of no clinical significance.
In rare cases there may be non-degenerative atypia in the form of prominent nucleoli, foci of atypical squamous metaplasia, or areas with dysplasia. Some authors recommend that such cases should be best considered as urothelial carcinomas with inverted pattern. Others recommend calling them IUPs with a comment on the presence of atypia. In any case, close follow-up with periodic cystoscopic examination is recommended.
In rare cases there may be non-degenerative atypia in the form of prominent nucleoli, foci of atypical squamous metaplasia, or areas with dysplasia. Some authors recommend that such cases should be best considered as urothelial carcinomas with inverted pattern. Others recommend calling them IUPs with a comment on the presence of atypia. In any case, close follow-up with periodic cystoscopic examination is recommended.