WHO / ISUP classification

Author: Sean Williamson, M.D. (see Authors page)

Revised: 7 September 2017, last major update June 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: "WHO classification" ureters OR (ISUP classification ureters)

Cite this page: Williamson, S. WHO / ISUP - general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uretersWHOgen.html. Accessed July 21st, 2018.
Prior classification systems
  • Ash (1940): classify as transitional cell carcinoma grades 1 - 4; grade 1 comparable to papilloma, grade 2 comparable to low grade; grade 3 (most) and 4 comparable to high grade
  • Mostofi (1960): grade 1 called papilloma and not carcinoma
  • World Health Organization / International Society of Urologic Pathologists consensus classification that is controversial for some lesions (low malignant potential)
  • Major changes from prior systems are that papillary urothelial carcinomas must exhibit atypia and carcinoma in situ need not be full thickness
  • WHO / ISUP grade correlates with tumor stage and recurrence
  • Website tutorial (Johns Hopkins University: The WHO / ISUP Consensus Classification of Urothelial Neoplasms) has further discussion; free but requires registration
  • Normal:
    • Flat mucosa without overt increase in thickness (usually normal urothelium considered 3 - 7 cell layers, depending on degree of distension)
    • Includes a spectrum of slight disorganization of cells and nuclear pleomorphism that formerly might be considered mild dysplasia
    • Size of normal urothelial cells is 3x lymphocytes
  • Hyperplasia:
    • Flat or papillary
  • Flat lesions with atypia:
    • Reactive
    • Unknown significance
    • Dysplasia (low grade intra-urothelial neoplasia)
    • CIS (high grade intra-urothelial neoplasia)
  • Papillary urothelial neoplasms:
    • Papilloma
    • Inverted papilloma
    • Papillary urothelial neoplasm of low malignant potential (PUNLMP)
    • Low grade papillary urothelial carcinoma
    • High grade papillary urothelial carcinoma
  • Invasive urothelial neoplasms:
    • Lamina propria invasion
    • Muscularis propria invasion (for bladder)
  • Low grade neoplasms:
    • Includes papilloma
    • Inverted papilloma
    • Papillary urothelial neoplasm of low malignant potential (PUNLMP)
    • Low grade papillary urothelial neoplasms (urothelial carcinoma grades 1 / 3 and some grade 2 / 3)