Papillary urothelial neoplasm of low malignant potential (PUN-LMP) was introduced as a noninvasive, noncancerous lesion and a separate grade category. The retrospective study evaluates prognostic value of PUN-LMP on 3,311 primary Ta bladder tumors from 17 hospitals in Europe and Canada.
The proportion of PUN-LMP has decreased to very low levels in the last decade. Contrary to its reconfirmation in the WHO 2016 classification, our results do not support the continued use of PUN-LMP as a separate grade category in Ta tumors because of the similar prognosis for PUN-LMP and Ta-LG carcinomas.