Transitional Cell Carcinoma of the Bladder in a 12-Year-Old Gelding

• Transitional cell carcinoma is rare in the equine clinical setting.
• Cyclooxygenase 2 nonsteroidal anti-inflammatory drugs can be used for the treatment.
• Perform immunohistochemistry to evaluate effectiveness of therapy and prognosis.

A 12-year-old Dutch Warmblood gelding was brought to the Veterinary Teaching Hospital (OVUD) of the University of Perugia (Italy) because of a six month history of hematuria and stranguria. A large mass in the bladder was detected by cystoscopy, and a transitional cell carcinoma was diagnosed. Further diagnostic investigations did not detect any metastatic spreading, and a therapy with cyclooxygenase 2 (COX-2) selective nonsteroidal anti-inflammatory drugs (NSAIDs) and antibiotics was started. After 1 month of therapy, the horse had worsened and euthanasia was elected. Necropsy showed local and systemic spreading of the tumor. Transitional cell carcinoma is a rare tumor in the horse. However, it should be considered in the differential diagnosis list for chronic hematuria and stranguria. A complete clinical and laboratory examination is required to have a definitive prognosis. The use of COX-2 selective NSAIDs has been advocated in some cases of carcinoma in both human and veterinary medicine, alone or together with the removal of the primary tumor with good results. Immunohistochemistry should be performed to detect the expression of COX-2 receptors by neoplastic cells to confirm the effectiveness of the NSAIDs therapy: a negative result denotes a poor prognosis and should call for euthanasia, especially if large tumors are detected.