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Papillary urothelial neoplasm of low malignant potential

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PUNLMP (Papillary Urothelial Neoplasm of Low Malignant Potential)
Micrograph of a PUNLMP. Intermediate magnification. H&E stain.
SpecialtyUrology, pathology

Papillary urothelial neoplasm of low malignant potential (PUNLMP) is an exophytic (outward growing), (microscopically) nipple-shaped (or papillary) pre-malignant growth of the lining of the upper genitourinary tract (the urothelium), which includes the renal pelvis, ureters, urinary bladder and part of the urethra.

PUNLMP is pronounced pun-lump, like the words pun and lump.

As their name suggests, PUNLMPs are neoplasms, i.e. clonal cellular proliferations, that are thought to have a low probability of developing into urothelial cancer, i.e. a malignancy such as bladder cancer.

Signs and symptoms

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PUNLMPs can lead to blood in the urine (hematuria) or may be asymptomatic.[citation needed]

Diagnosis

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Micrograph of a PUNLMP showing characteristic features (see text). H&E stain.

PUNLMPs are exophytic lesions that appear friable to the naked eye and when imaged during cystoscopy. They are definitively diagnosed after removal by microscopic examination by pathologists.[citation needed]

Histologically, they have a papillary architecture with slender fibro vascular cores and rare basal mitoses. The papillae rarely fuse and uncommonly branch. Cytologically, they have uniform nuclear enlargement.[citation needed]

They cannot be reliably differentiated from low grade papillary urothelial carcinomas using cytology,[1] and their diagnosis (vis-a-vis low grade papillary urothelial carcinoma) has a poor inter-rater reliability.[2]

Pathologic grading and staging tumors are: graded by the degree of cellular atypia (G1->G3), and staged:[citation needed]

  • papilloma
  • papillary tumor of low malignant potential (PTLMP)
  • papillary urothelial carcinomas low grade
  • papillary urothelial carcinomas high grade.

Differential diagnosis

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Immunohistochemistry for p53 can help distinguish a PUNLMP from a low grade urothelial carcinoma. Overexpression is seen in 75% of low-grade urothelial carcinomas and only 10% of PUNLMP.[3][4]
  • Papilloma.
  • Low grade papillary urothelial carcinoma.

Treatment

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PUNLMPs are treated like non-invasive low grade papillary urothelial carcinomas,[1] excision and regular follow-up cystoscopies.

There is a rare occurrence of a pelvic recurrence of a low-grade superficial TCC after cystectomy. Delayed presentation with recurrent low-grade urothelial carcinoma is an unusual entity and potential mechanism of traumatic implantation should be considered. Characteristically low-grade tumors are resistant to systemic chemotherapy and curative-intent surgical resection of the tumor should be considered.[citation needed]

References

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  1. ^ a b Jones TD, Cheng L (June 2006). "Papillary urothelial neoplasm of low malignant potential: evolving terminology and concepts". J. Urol. 175 (6): 1995–2003. doi:10.1016/S0022-5347(06)00267-9. PMID 16697785.
  2. ^ MacLennan GT, Kirkali Z, Cheng L (April 2007). "Histologic grading of noninvasive papillary urothelial neoplasms". Eur. Urol. 51 (4): 889–97, discussion 897–8. doi:10.1016/j.eururo.2006.10.037. PMID 17095142.
  3. ^ Image is taken from following source, with some modification by Mikael Häggström, MD:
    - Schallenberg S, Plage H, Hofbauer S, Furlano K, Weinberger S, Bruch PG; et al. (2023). "Altered p53/p16 expression is linked to urothelial carcinoma progression but largely unrelated to prognosis in muscle-invasive tumors". Acta Oncol: 1–10. doi:10.1080/0284186X.2023.2277344. PMID 37938166.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Source for role in distinguishing PUNLMP from low-grade carcinoma:
    - Kalantari MR, Ahmadnia H (2007). "P53 overexpression in bladder urothelial neoplasms: new aspect of World Health Organization/International Society of Urological Pathology classification". Urol J. 4 (4): 230–3. PMID 18270948.