[786] Non-Invasive Micropapillary Urothelial Carcinoma: A Report of 18 Cases

Ali Amin, Jonathan I Epstein. The Johns Hopkins Hospital, Baltimore

Background: Invasive micropapillary urothelial carcinoma is a variant of urothelial carcinoma that is considered more aggressive since it often presents at higher stage. Although typically not specified, micropapillary urothelial carcinoma usually refers to invasive tumor although non-invasive micropapillary urothelial carcinoma also exists. The current study analyzes the morphology and outcome of non-invasive micropapillary urothelial carcinoma unaccompanied by invasive carcinoma.
Design: 18 non-invasive micropapillary urothelial carcinomas (w/o a history of prior urothelial carcinoma) were identified in our archives (2000-2011). Progression was defined as recurrent urothelial carcinoma of higher stage.
Results: 88% were male, with a mean age 71.9yrs. Non-invasive micropapillary urothelial carcinoma was seen in 2 patterns: 1) as a variant of non-invasive high grade papillary urothelial carcinoma (HGPAP) (n=14 cases); and 2) as a variant of CIS (n=4 cases, 1 also with HGPAP). All were identified on biopsy specimens. Data on the initial treatments were available in 12 patients and included: Surveillance (n=5); BCG (n=5); intravesicle chemotherapy (n=1); and radical cystectomy (n=1). Of the 11 cases with follow-up, 4 patients experienced recurrence treated with BCG in 2 cases and cystoprostatectomy in 2 cases. All patients were disease free at last follow-up (Mean 33.9 months; Median 24 months; Range 5-96 months).
Conclusions: The current study is the first to systematically analyze the morphology and outcome of non-invasive micropapillary urothelial carcinoma unaccompanied by invasive carcinoma. Our results demonstrate that recurrence, progression, and survival rates in non-invasive micropapillary urothelial carcinoma are favorable. It follows more or less a similar clinical course as HGPAP and CIS. Often the term “micropapillary urothelial carcinoma” is used without specifying whether invasive or non-invasive. Invasive micropapillary urothelial carcinoma is considered very aggressive where some authorities have recommended radical cystectomy if found on TUR even in the absence of documented muscularis propria invasion. It is therefore critical to differentiate and clearly specify whether micropapillary urothelial carcinoma is invasive or non-invasive in Pathology reports. Furthermore, recognition and reporting non-invasive micropapillary urothelial carcinoma will hopefully lead to larger studies adding to our understanding of its biology.
Category: Genitourinary (including renal tumors)

Tuesday, March 20, 2012 1:00 PM

Platform Session: Section A, Tuesday Afternoon

 

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