Serous Carcinoma Mimicking Primary Urothelial Carcinoma on Clinical Evaluation and Pathology: A Potential Diagnostic Pitfall

Context.— Serous carcinomaof the gynecologic tract often involves the external bladder wall and can occasionally mimic primary urothelial carcinomaof the bladder. Objective.— To define the spectrum of morphologic and immunohistochemical features that characterize serous carcinomainvolving the bladder wall and its distinction from urothelial carcinoma. Design.— We reviewed all cases of serous carcinomasecondarily involving the bladder wall from the University of California San Diego and Polytechnic Institute for histopathologic and immunohistochemical features. Results.— We identified 20 cases of Mullerian high-grade serous carcinomainvolving the bladder wall. Five cases were clinical mimics of urothelial carcinoma, including 2 cases that presented as a large, transmural, primary bladder mass without precedent gynecologic history in women younger than 60 years, and 3 cases presumed to be new bladder carcinomaoccurring distant to a serous carcinomadiagnosis. A subset of cases were morphologic mimics ...