Table of Contents
Definition / general | Terminology | ICD coding | Epidemiology | Sites | Clinical features | Prognostic factors | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Molecular / cytogenetics description | Differential diagnosisCite 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
- Incidence of 3 cases / 100K individuals per year
- Male to female ratio 5:1, mean age 65 +/- 14 years
- In one US study, represented 25% of bladder tumors (Scand J Urol Nephrol 2008;42:237)
- In children, represent 50% of bladder tumors (BJU Int 2010;106:557)
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
Images hosted on other servers:
Intermediate magnification
Low magnification
PUNLMP
PUNLMP
Molecular / cytogenetics description
- No specific changes known
Differential diagnosis
- Low grade papillary urothelial carcinoma: small cells more densely arranged on fibrovascular stalks, nuclear are rounder, more nuclear pleomorphism
- Papilloma: no atypia
- Polypoid / papillary cystitis: cystoscopic impression is inflammatory lesion, appears reactive at low power with inflamed background that is edematous or densely fibrous with predominantly simple, non-branching, broad-based fronds of relatively normal thickness (Am J Surg Pathol 2008;32:758)
