| PUNLMP (Papillary Urothelial Neoplasm of Low Malignant Potential) | |
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| Classification and external resources | |
Micrograph of a PUNLMP. Intermediate magnification. H&E stain. |
In urologic pathology, PUNLMP, short for papillary urothelial neoplasm of low malignant potential, 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.
They are thought to be relatively rare; one study of two-hundred papillary urothelial lesions found a prevalence of 0-3.5%.[1]
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PUNLMPs can lead to blood in the urine (hematuria) or may be asymptomatic.
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.
Histologically, they have a papillary architecture with slender fibrovascular cores and rare basal mitoses. The papillae rarely fuse and uncommonly branch. Cytologically, they have uniform nuclear enlargement.
They cannot be reliably differentiated from low grade papillary urothelial carcinomas using cytology,[2] and their diagnosis (vis-a-vis low grade papillary urothelial carcinoma) has a poor inter-rater reliability.[3]
PUNLMPs are treated like non-invasive low grade papillary urothelial carcinomas,[2] excision and regular follow-up cystoscopies.