Bladder, ureter & renal pelvis
Urothelial neoplasms-noninvasive
Papillary urothelial neoplasm of low malignant potential


Topic Completed: 1 November 2016

Minor changes: 7 August 2020

Copyright: 2016-2020, PathologyOutlines.com, Inc.

PubMed Search: Papillary urothelial neoplasm of low malignant potential

Page views in 2020 to date: 1,582
Cite this page: Gaumann A. Papillary urothelial neoplasm of low malignant potential. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bladderPUNLMP.html. Accessed August 7th, 2020.
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
Terminology
  • PUNLMP
ICD coding
  • ICD-O: 8130/1
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
Microscopic (histologic) 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
Microscopic (histologic) images

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Intermediate magnification

Low magnification

PUNLMP

PUNLMP

Molecular / cytogenetics description
  • No specific changes known
Differential diagnosis
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