title: The 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs-Part B: Prostate and Bladder Tumours.
abstract: It has been 12 yr since the publication of the last World Health Organization (WHO) classification of tumours of the prostate and bladder. During this time, significant new knowledge has been generated about the pathology and genetics of these tumours. Intraductal carcinoma of the prostate is a newly recognized entity in the 2016 WHO classification. In most cases, it represents intraductal spread of aggressive prostatic carcinoma and should be separated from high-grade prostatic intraepithelial neoplasia. New acinar adenocarcinoma variants are microcystic adenocarcinoma and pleomorphic giant cell adenocarcinoma. Modifications to the Gleason grading system are incorporated into the 2016 WHO section on grading of prostate cancer, and it is recommended that the percentage of pattern 4 should be reported for Gleason score 7. The new WHO classification further recommends the recently developed prostate cancer grade grouping with five grade groups. For bladder cancer, the 2016 WHO classification continues to recommend the 1997 International Society of Urological Pathology grading classification. Newly described or better defined noninvasive urothelial lesions include urothelial dysplasia and urothelial proliferation of uncertain malignant potential, which is frequently identified in patients with a prior history of urothelial carcinoma. Invasive urothelial carcinoma with divergent differentiation refers to tumours with some percentage of "usual type" urothelial carcinoma combined with other morphologies. Pathologists should mention the percentage of divergent histologies in the pathology report.
  
  
  
  Intraductal carcinoma of the prostate is a newly recognized entity in the 2016 World Health Organization classification. Better defined noninvasive urothelial lesions include urothelial dysplasia and urothelial proliferation of uncertain malignant potential.
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Humphrey
authors.affiliation: Department of Pathology, University Hospital Zurich, Zurich, Switzerland. Electronic address: holger.moch@usz.ch.
authors.forename: Holger
authors.initials: H
authors.lastname: Moch
authors.affiliation: Instituto de Patología e Investigación, Facultad de Ciencias Médicas, Universidad Nacional de Asunción, San Lorenzo, Paraguay.
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Cubilla
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University Health Partners, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Ulbright
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Victor E
authors.initials: VE
authors.lastname: Reuter
mesh_terms: D002277:Carcinoma / Q000145:classification* / Q000235:genetics / Q000473:pathology; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D011471:Prostatic Neoplasms / Q000145:classification* / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000145:classification* / Q000473:pathology; D014944:World Health Organization
keywords: Bladder; Prostate; WHO classification