[828] Micropapillary Urothelial Carcinoma of the Urinary Bladder: A Clinicopathologic Analysis of 24 Cases

N Edgerton, SJ Sirintrapun, MJ Munoz, AO Osunkoya. Emory University School of Medicine, Atlanta, GA

Background: Micropapillary urothelial carcinoma (MUCa) of the urinary bladder is relatively rare. We report one of the largest series to date of MUCa with follow up information.
Design: The surgical pathology and expert consultation files at our institution were searched for MUCa of the bladder diagnosed in transurethral resection of bladder tumor (TURBT) and radical cystectomy/cystoprostatectomy specimens from 2002 to 2009. Only patients with available follow up information were selected. Tumor volumes were stratified based on percentage of the micropapillary component (MC) <50%, >50% and 100%. Other pathologic parameters were obtained on all patients.
Results: 24 cases of MUCa with available follow up data were identified. The mean patient age was 71 years (range 55-86 years), with a male to female ratio of 3:1. 6 cases (6/24; 25%) were composed entirely of MC; 12 cases (12/24. 50%) showed >50% MC; and 6 cases (6/24; 25%) showed <50% MC. 7 cases (7/24; 29%) were also composed of variable amounts of nested, clear cell, signet ring cell pattern and adenocarcinoma. Of the 14 patients that opted for radical cystectomy/cystoprostatectomy as monotherapy, the majority (10/14; 71%) had pT3 or more advanced staged disease. 4 patients (4/24; 17%) had neoadjuvant chemotherapy prior to radical cystectomy/cystoprostatectomy and showed minimal residual disease with urothelial carcinoma in situ. 3 patients (3/24; 13%) had local extension into surrounding organs (prostate, cervix, ovary) pT4 showing 100% MC. 19 cases (19/24; 79%) had angiolymphatic invasion. Of the 16 cases in which nodal status was known, 9 (9/16; 56%) were positive; 5 cases (5/9; 55%) showing metastases composed entirely of MUCa. Mean duration of follow up of all patients was 16 months (range 1-59 months). 11 patients (11/24; 46%) died of disease. The tumors in most patients that died of disease 9/11(81%) were composed of 100% MUCa or >50% MUCa. Mean survival time was 14 months.
Conclusions: Our study confirms that MUCa is typically aggressive and presents with advanced stage disease in most cases. MUCa may also be associated with other aggressive variants of urothelial carcinoma. We recommend reporting the percentage of MC in these tumors in view of the direct relationship to adverse clinical outcome. It is also critical to make an accurate diagnosis of this entity especially in relatively small biopsies or TURBT specimens, because urologists may proceed to cystectomy/cystoprostatectomy based on pT1 disease.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 117, Monday Morning


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