[1049] Primary Papillary Urothelial Neoplasm of Low Malignant Potential (PUNLMP) Including PUNLMP with Inverted Growth: Outcome Analysis

Cheng Wang, Jay P Maxwell, Asli Yilmaz, Tarek A Bismar, Kiril Trpkov. Calgary Laboratory Services and University of Calgary, Calgary, Canada

Background: Few single-center studies addressed the long-term clinical outcome for patients with PUNLMP. Many of the previous studies, however, included both de novo (Primary-PUNLMP) and Secondary-PUNLMP, diagnosed during surveillance for higher grade urothelial neoplasm. The previous studies typically included less than 100 patients.
Design: We searched our institutional information system for all Primary-PUNLMP including PUNLMP with inverted growth, diagnosed between 01/2000 and 12/2009. All cases with a previous history of higher grade urothelial neoplasm (Secondary-PUNLMP) were excluded. The follow-up (F/U) was obtained by review of the electronic medical records in our centralized urology and uropathology practice for the region. On F/U, recurrence was defined as any subsequent neoplastic bladder lesion. Progression was defined as subsequent high-grade or invasive recurrent tumor, including carcinoma in-situ or dysplasia.
Results: We identified a total of 196 Primary-PUNLMP (all bladder location except 1 in renal pelvis), including 12 (6%) with inverted pattern. Mean patient age was 64 years (median 66, range 19 to 92) with M:F ratio of 1.8:1. Mean F/U was 65 months (range 10 to 133). Recurrence was documented in 45 (23%) patients (median number of recurrencies 1, range 1-7); 35 (18%) of recurrencies were without progression. Multiple recurrences occurred in 37% (13/35) patients who did not progress. In 10 (5%) patients, there was progression to high-grade carcinoma: 7 non-invasive and 3 invasive, of which 1 into lamina propria and 2 into muscularis propria. In 6 patients progression occured directly into high-grade, while in 4, progression occured after subsequent PUNLMP (2) or low-grade (2) carcinoma. All patients who progressed were male with a mean age of 71 years (range, 50-87). All recurrent neoplasms after Primary-PUNLMP were in the bladder, except one case in the renal pelvis. The mean time to recurrence without subsequent progression was 31 monts (range, 5-87). The mean time to progression was 39 months (range, 4-101). None of the patients with Primary-PUNLMP with inverted growth pattern had a documented recurrence or progression. No progression with metastatic disease was found in any patient.
Conclusions: We found an overall recurrence rate of 23% and a progression rate of 5% in a large contemporary cohort of Primary-PUNLMP. Ongoing surveillance is particularly warranted for older males (≥50 years) diagnosed with Primary-PUNLMP. The subgroup of patients with Primary-PUNLMP with inverted growth pattern had a good outcome in this study.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 126, Monday Morning


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