Ureterocolonic Anastomosis in a Dog with Transitional Cell Carcinoma in the Vesical Trigone

Background: Primary bladder tumors are rare in dogs, in spite of that, the transitional cell carcinoma (TCC) is the malignant tumor that most affects dogs. The TCC usually begins in the vesical trigone and extends into the bladder, and may cause partial or complete obstruction of the urinary flow. The treatment with cystectomy and urinary diversion in veterinary medicine is not usual probably because the partial cystectomy has low success and ureterocolonic anastomosis can cause pyelonephritis and/ or urinary incontinence. This paper describes the cystectomy surgery and ureterocolonic anastomosis in a dog with TCC in the bladder and bilateral hydronephrosis. Case: A 8-year-old, male, not castrated, Pitbull was referred to the Veterinary Clinic Hospital - UFRGS. The patient had progressive weight loss, low appetite, dysuria, and hematuria. Abdominal ultrasound showed bilaterally hydronephrosis, kidney pelvis and ureter dilatation. The mesogastric region presented a mass measuring about 14 cm. An exploratory laparotomy was request by the responsible veterinarian. A mass, measuring about 20 cm was observed in the spleen and a splenectomy was requested. An increased of the kidney’s volume and an expansion of the renal pelvis and ureter were observed. The bladder wall had thickened and presented a firm consistency, an ureterocolonic anastomosis was requested by the responsible veterinarian. Total cystectomy was performed in a second surgical procedure. Six days after the second surgery the patient condition got worse. The dog presented abdominal pain signals and pale mucous membranes. The hematological and biochemistry analysis findings were, severe anemia, and elevated serum creatinine (6.12 mg/dL) and urea (263 mg/dL) levels. Based on severity of clinical signs and unfavorable prognosis the owners elected for euthanasia. Necropsy revealed a viscous material into the left ureter and in left renal pelvis, and papillary necrosis in the right kidney. The histologic assessment revealed tumor cells in regional lymph nodes and lungs. Discussion: The urinary diversion when consist of total cystectomy and ureteral transplantation to the gastrointestinal tract can be considered a therapeutic option in cases where the trigone is affected. In this study an ureterocolonic anastomosis was requested due to bilateral ureteral obstruction caused by TCC involving the trigone. Neurological and gastrointestinal signs, elevated serum creatinine levels and pyelonephritis may occur after surgery. Neurological signs were not observed. The dog, in the present case report, had already azotemia in pre-surgical examinations, probably caused by bilateral ureteral obstruction. One of the reasons for the increase in postoperative serum creatinine levels is chronic renal failure caused by ascending infection or post-renal obstruction. Another reason could also be reabsorption of the metabolite through the colon. Necropsy findings were ascending infection and pyelonephritis. Dilation of ureter at the time of surgery may have predisposed to the ascending infection. In previous studies aggressive surgical therapy did not result in a significant increase in survival time in dogs when compared to chemotherapy. Most dogs presented metastases, observed most frequently in lymph nodes and lungs. In this report the surgery was performed in an attempt to improve kidney function and life quality of the patient during hospitalization. The prognosis was considered unfavorable because of the advanced stage of the disease and kidney failure. The absence of an early diagnosis and inability to start early chemotherapy may result in a reduced in the survival time of these patients. Keywords: vesical neoplasm, hydronephrosis, urinary diversion, dogs.