Bladder
Urothelial neoplasms-noninvasive
Papillary urothelial neoplasm of low malignant potential

Author: Andreas Gaumann, M.D. (see Authors page)

Revised: 12 July 2016, last major update December 2014

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Papillary urothelial neoplasm of low malignant potential [title]
Definition / General
  • Resembles the exophytic urothelial papilloma, but with increased cellular proliferation exceeding the thickness of normal urothelium; appears to lack the capacity to invade or metastasize
  • ICD-O: 8130/1
Terminology
  • PUNLUMP: papillary urothelial neoplasm of low malignant potential
Epidemiology
Sites
  • Preferred sites are the lateral posterior walls and ureteric orifices
Clinical Features
  • Presents with gross or microscopic hematuria
  • May resemble "seaweed in ocean" at cystoscopy
  • 1/3 recur, 5% as higher grade
  • 10 year survival 95% or more
  • Rarely associated with invasion or metastases
  • Add to report:
    • "Patients with these tumors are at risk of developing new bladder tumors ("recurrence"), usually of a similar histology. However, since these subsequent lesions occasionally manifest as urothelial carcinoma, follow up is warranted"
  • Have lower MIB-1, p53 and mitotic counts than low grade papillary carcinomas, and higher median disease free survival (76 vs. 15 months, Am J Surg Pathol 2001;25:1528)
Prognostic Factors
  • Excellent prognosis when totally excised
  • Tumors with focal high grade carcinoma act like high grade carcinomas
  • Tumors with high Ki-67/MIB1 are more likely to recur (Cancer 2002;95:784)
Gross Description
  • 1-2 cm regular polypoid tumors
Micro Description
  • Orderly arrangement of cells within papillae with minimal architectural abnormalities and minimal nuclear atypia, regardless of cell thickness
  • Thicker epithelium than papilloma, increase in nuclear size and hyperchromasia compared to papilloma
  • Reduced cytoplasmic clearing compared to normal urothelium
  • Neoplastic cells may extend down the stalk onto adjacent flat urothelium
  • Mitotic figures, if present, are usually confined to basal layer
Micro Images

Images hosted on other servers:

Intermediate magnification

Low magnification

PUNLMP

Urothelial thickening

Homogenous monotonous appearance


Orderly arrangement of urothelial cells

Urothelial lining is thickened

Examples of papillary tumor of low malignant potential

H&E, CD44+, CK20+



Images hosted on Flickr:

PUNLMP


Molecular / Cytogenetics Description
  • No specific changes known
Differential Diagnosis