title: Pseudocarcinomatous hyperplasia of the urinary bladder.
abstract: We review the morphology and differential diagnoses of pseudocarcinomatous hyperplasia of the bladder, using a study case to illustrate the discussion. Pseudocarcinomatous hyperplasia is a rare, reactive response to an ischemic insult, classically to radiation therapy, and consists of proliferative, pseudoinfiltrative urothelial nests within the stroma. The presence of background radiation therapy-related changes, such as numerous dilated thrombosed vessels, reactive-appearing endothelial and stromal cells, edema, and hemorrhage, can provide clues to the diagnosis. The main differential diagnoses include invasive urothelial carcinoma and the nested variant of urothelial carcinoma; morphologic features, such as the presence or absence of background therapy-related changes and the architecture and the cytologic atypia of the nests, can help distinguish between pseudocarcinomatous hyperplasia and urothelial carcinoma.
authors.affiliation: From the Department of Pathology, University of Michigan Medical School, Ann Arbor.
authors.forename: Angela
authors.initials: A
authors.lastname: Wu
mesh_terms: D000230:Adenocarcinoma / Q000150:complications / Q000532:radiotherapy; D002277:Carcinoma / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D003556:Cystitis / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology / Q000503:physiopathology; D003937:Diagnosis, Differential; D006417:Hematuria / Q000209:etiology; D006801:Humans; D006965:Hyperplasia; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000150:complications / Q000532:radiotherapy; D011832:Radiation Injuries / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D001743:Urinary Bladder / Q000276:immunology / Q000473:pathology* / Q000528:radiation effects; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D019459:Urothelium / Q000276:immunology / Q000473:pathology / Q000528:radiation effects