Flat Urothelial Hyperplasia
There is appreciable thickening of the urothelium which still shows orderly maturation to the surface and lacks cytologic atypia. Flat urothelial hyperplasia may occur de novo, where it appears to have no malignant potential. It may also be seen in conjuction with cystitis, bladder calculi, and urothelial neoplasms. Several fragments/foci should be examined to prevent overdiagnosing a single focus with tangential sectioning as flat hyperplasia.