[829] In Situ Adenocarcinoma of the Bladder in the Absence of Infiltrating Carcinoma: Report of 24 Cases

JS Miller, JI Epstein. Johns Hopkins Hospital, Baltimore

Background: In situ adenocarcinoma of the bladder in the absence of infiltrating carcinoma is rare and the clinical outcomes for these patients are not well-characterized.
Design: 24 cases of in situ bladder adenocarcinoma on biopsy (n=20) or TUR (n=4) without an associated invasive component were retrieved from the consult files of one of the authors. The following cases were excluded: 1) CIS demonstrating 'gland-like' or 'pseudoglandular' components; 2) villous adenoma with in situ adenocarcinoma; and 3) intestinal metaplasia with in situ adenocarcinoma.
Results: Mean patient age at diagnosis was 70 years (range 48 to 87) and 75% were male. Half of the cases were pure in situ adenocarcinoma; half were associated with either CIS or high-grade noninvasive papillary carcinoma. The in situ adenocarcinoma component consisted of one or more patterns: papillary (46% of cases), glandular (42%), cribriform (33%), and flat (25%). Mitoses, apoptosis, and necrosis were identified in 83%, 67%, and 17% of the biopsies, respectively. One case was a recent diagnosis, and 5 either refused treatment or were lost to follow-up. Of the 18 patients with available follow-up information, 9 (50%) were treated with BCG and/or cystectomy and did not develop invasive carcinoma; the remaining 9 (50%) eventually developed an invasive bladder tumor. Of these, 2 were small cell carcinoma, 3 were poorly-differentiated urothelial carcinoma (2 of these developed widespread metastases), and 4 were urothelial carcinoma, not otherwise specified. In both instances of eventual small cell carcinoma, and in 2 of the 3 cases of poorly-differentiated urothelial carcinoma, the initial biopsy consisted of pure in situ adenocarcinoma without CIS or noninvasive papillary carcinoma. Of note, none of the patients in the study developed invasive adenocarcinoma.
Conclusions: Pure in situ adenocarcinoma is associated with an increased risk of developing invasive urothelial carcinoma. Furthermore, there seems to be a correlation between these in situ lesions and eventual high-grade, prognostically-poor invasive bladder carcinomas such as small cell carcinoma and poorly-differentiated urothelial carcinoma. This is particularly notable in cases with an initial biopsy that reveals in situ adenocarcinoma alone, without associated CIS or noninvasive papillary carcinoma. While in situ and invasive adenocarcinomas commonly coexist, the finding of purely in situ adenocarcinoma does not seem to have an association with the development of eventual invasive adenocarcinoma of the bladder.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 2:45 PM

Platform Session: Section A, Monday Afternoon