Characterization and treatment of transitional cell carcinoma of the abdominal wall in dogs: 24 cases (1985-2010).

OBJECTIVE To determine uroplakin III expression, potential etiologic factors, biological behavior, and treatment response of transitional cell carcinoma (TCC) in the abdominal wall (ABWTCC) in dogs. DESIGN Retrospective case series. ANIMALS 24 dogs with TCC of the urinary tract that also had histopathologic confirmation of ABWTCC. PROCEDURES Medical records, histologic slides, radiographs, and ultrasonographic images of dogs with ABWTCC between July 1, 1985, and December 31, 2010, were reviewed. In available tissue specimens, immunohistochemistry was used to detect uroplakin III expression in the ABWTCC and in the primary tumor. RESULTS The ABWTCC lesions ranged from < 2 to > 20 cm in diameter. Uroplakin III was expressed in 19 of 20 primary tumors and 17 of 17 ABWTCCs. Transitional cell carcinoma in the abdominal wall developed significantly more often in dogs that had undergone cystotomy (18/177 [10.2%]) than in those that had not (6/367 [1.6%]). In 1 dog that had not undergone cystotomy, TCC had invaded through the urinary bladder wall and spread down the median ligament to the abdominal wall. None of 18 dogs that received anticancer drugs had remission of the ABWTCC once clinically detected; median survival time after ABWTCC detection was 57 days (range, 0 to 324 days). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that ABWTCC is uncommon, but once TCC becomes established and clinically detectable in the abdominal wall, it carries a poor prognosis. It is crucial to minimize risk of TCC seeding at surgery. Percutaneous sampling of TCC should be avoided. Uroplakin III is commonly expressed in ABWTCC.