[801] When Worlds Collide: A Series of Genitourinary Collision Tumors

Waseem Anani, Somak Roy, Milon Amin, Uma Rao, Liron Pantanowitz, Anil Parwani. University of Pittsburgh Medical Center, Pittsburgh, PA

Background: Primary genitourinary neoplasms as well as metastasis from other sites to the genitourinary tract are common. In contrast, collision tumors, characterized by coexistence of phenotypically and genotypically distinct tumors at the same site, are distinctly rare in the genitourinary tract and pose a diagnostic challenge. The goal of this study is to present a series of such cases from a single institution highlighting the unusual clinicopathologic features of these tumors.
Design: Nine cases were retrospectively identified from our surgical pathology files and included internal and consultation cases (2006-2012). All tumors were identified by H&E and immunohistochemistry as distinct primary neoplasms. In select cases, the final diagnosis was substantiated by fluorescence in-situ hybridization.
Results: The study included 9 patients, 8 males and 1 female ranging in age from 34-84 years (mean 66.3 years). Collision tumors composed 7 of the 8 cases with the site of the collision as follows: kidney (6), bladder (2), and pelvis (1). All but one of the collision tumors involved two malignant neoplasms.

Collision Tumor Cases
CasePrimary TumorSecondary TumorLocationAgeSex
1Chromophobe Renal Cell CarcinomaNeuroendocrine/Carcinoid TumorKidney34M
2Clear Cell Renal Cell CarcinomaPulmonary AdenocarcinomaKidney57M
3Clear Cell Renal Cell CarcinomaPoorly Differentiated Carcinoma of Urothelial OriginKidney64M
4AngiomyolipomaMammary CarcinomaKidney67F
5Clear Cell Renal Cell CarcinomaChromophobe Renal Cell CarcinomaKidney76M
6Chromophobe Renal Cell CarcinomaPapillary Renal Cell CarcinomaKidney81M
7Pleomorphic LiposarcomaProstatic AdenocarcinomaPelvis70M
8Urothelial CarcinomaProstatic AdenocarcinomaBladder73M
9Urothelial CarcinomaProstatic AdenocarcinomaBladder84M

Conclusions: To our knowledge, this is the largest report of collision neoplasms of genitourinary origin. Diagnosis of collision tumors in the genitourinary tract is a perplexing task and awareness about these rare entities, thorough sampling of the tumor mass and appropriate use of ancillary techniques are recommendations for avoiding incorrect diagnosis, and pathologic staging.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 176, Wednesday Afternoon


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