Urothelial carcinoma associated with a long-term indwelling cystostomy component of a subcutaneous ureteral bypass device in a domestic shorthair cat.

Urothelial carcinoma (UC) occurs uncommonly in cats and no association has previously been observed with long-term indwelling urinary implants. An 18-year-old male castrated domestic shorthair cat initially was presented for hematuria, leading to the diagnosis of a right-sided ureterolithiasis and severe pyelectasia on ultrasound examination, prompting right-sided subcutaneous ureteral bypass (SUB) device placement. The cat subsequently had intermittent hematuria and dysuria, without ultrasonographic abnormality of the bladder or positive urine culture. Thirteen months later the patient developed refractory lower urinary tract signs, azotemia, a proliferative mass in the region of the cystostomy tube component of the SUB device and evidence of left ureteral obstruction. Cystostomy tube revision and left-sided SUB device placement were performed, as well as a partial cystectomy for removal of the mass. Upon histopathology, the mass was diagnosed as a UC. To our knowledge, UC associated with a long-term indwelling cystostomy catheter component of a SUB device has not been reported in veterinary medicine.