Context.-Urothelial proliferation of unknown malignant potential (UPUMP) is a 2016 World Health Organization classifier that encompasses prior categories of flat and papillary urothelial hyperplasia. In addition, UPUMP occurs in settings of both de novo and prior bladder neoplasia. Objective.-To identify UPUMP features associated with subsequent neoplastic development. Design.-Sixty-eight patients were identified from the archives, including 26 patients with de novo and 42 patients with prior bladder neoplasia. Patient slides and clinical course were reviewed. Results.-Patients with de novo UPUMP were detected through clinical findings (26/26; 100%), whereas surveillance cystoscopy primarily detected UPUMP in patients with prior neoplasia (29/42; 69%). Histopathologic criteria evaluated included urothelial hyperplasia, urothelial cytology, vascular ingrowth, denudation, inflammation, edema, and fibrosis. Mean clinical follow-up was 68.9 months in patients with de novo neoplasia and 69.5 months in patients with prior neoplasia. Subsequent neoplasia developed in 4 of 26 (15.4%) of patients with de novo UPUMP and was associated with cystoscopic papillary appearance (P ¼.02) or microscopic thin papillary ingrowths or papillations (P ¼.02; median time to progression, 4.1 months). Of 42 patients with prior neoplasia, 17 (40.5%) had subsequent neoplasia, significantly associated with an absence of prominent lamina propria edema (P,.001; median time to progression, 11.0 months). A higher rate of progression to high-grade disease was present in patients with a prior neoplasia versus those with de novo disease (58.9% versus 25%). Conclusions.-Urothelial proliferation of unknown malignant potential shows subsequent risk of neoplastic development of 17% in patients with de novo disease and 40% in patients with prior neoplasia. The greatest risk of progression is associated with early papillary formation.
ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Medical Laboratory Technology