[1006] Distinguishing Primary Urinary Bladder Adenocarcinoma from Secondary Involvement by Colorectal Adenocarcinoma: Extended Immunohistochemical Profiles Emphasizing Novel Markers

Qiu Rao, Sean R Williamson, Antonio Lopez-Beltran, Rodolfo Montironi, Wenbin Huang, John N Eble, David J Grignon, Michael O Koch, Muhammad T Idrees, Xiao-Jun Zhou, Lee Ann Baldridge, Liang Cheng. Indiana University School of Medicine, Indianapolis, IN; Nanjing University School of Medicine, Nanjing, China; Cordoba University, Cordoba, Spain; Polytechnic University of the Marche Region, United Hospitals, Ancona, Italy; Nanjing Medical University Affiliated Nanjing Hospital, Nanjing, China

Background: Glandular neoplasms involving the urinary bladder carry a challenging differential diagnosis including primary and secondary processes. We investigated the expression of cadherin-17 and GATA3 in primary bladder adenocarcinoma to evaluate potential diagnostic usefulness along with other commonly used markers.
Design: We analyzed cadherin-17, GATA3, β-catenin, and p63 expression in 25 primary bladder adenocarcinomas. Urothelial carcinoma with glandular differentiation (11), colorectal adenocarcinoma secondarily involving the bladder (25), and primary colorectal adenocarcinoma (22) were analyzed for comparison.
Results: Cadherin-17 was expressed in 23/25 primary bladder adenocarcinomas (92%), 23/25 colorectal adenocarcinomas involving the bladder (92%), 21/22 primary colorectal adenocarcinomas (95%), and entirely negative (0/11) in both components of urothelial carcinoma with glandular differentiation. In urothelial carcinoma with glandular differentiation, positive nuclear staining for GATA3 was evident in urothelial glandular component in 18% (2/11) and 9% (1/11), respectively, with additional tumors showing only cytoplasmic staining. Nuclear reactivity for GATA3 was not present in primary bladder adenocarcinoma and primary/secondary colorectal adenocarcinoma. Positive nuclear and cytoplasmic immunostaining for β-catenin was evident in 21/22 primary colorectal adenocarcinomas (95%) and 23/25 cases of secondary involvement by colorectal adenocarcinoma (92%). In contrast, positive membranous and cytoplasmic staining for β-catenin was observed in 23/25 primary bladder adenocarcinomas (92%) and 11/11 urothelial carcinomas with glandular differentiation (100%). p63 was expressed only in the urothelial component of urothelial carcinoma with glandular differentiation and not in the glandular component.
Conclusions: Cadherin-17 is a relatively specific and sensitive marker for primary bladder adenocarcinoma, distinguishing it from urothelial carcinoma with glandular differentiation. However, it does not distinguish primary bladder adenocarcinoma from secondary involvement by colorectal adenocarcinoma. The pattern of reactivity for β-catenin remains the most useful marker for distinguishing these two tumors.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 164, Wednesday Afternoon


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