Bladder tumors occur more frequently in female dogs and male cats. One known predisposing cause of transitional cell carcinoma is the previous administration of cyclophosphamide, a chemotherapeutic agent also used in treatment of some immune mediated disorders. In one report of dogs which developed cyclophosphamide-induced transitional cell carcinoma the duration of therapy ranged from 6 to 64 weeks. Urinary tract infection is often associated with a bladder tumor so treatment for UTI may temporarily improve the signs of a patient with a bladder tumor. Because of the similarity of signs and improvement following treatment with antibiotics, a diagnosis of neoplasia is often delayed.
Physical examination is usually normal but a caudel abdominal mass is occasionally palpated.
Bladder enlargement can be palpated in animals with urethral obstruction. Hematology and biochemical analysis are usually normal unless outflow obstruction is present in which case abnormalities will include azotemia, hyperphosphatemia and hyperkalemia. Dilation of the renal pelvis may be observed with ultrasound or intravenous pyelography in patients with ureteral obstruction at the trigone of the bladder. Cystoscopy is a relatively new technique which can be used to view inside the urethra and bladder. A sample of the mass in the bladder can be obtained by passing a urinary catheter and aspirating cells or by infusing saline into the bladder and washing out cells for cytologic examination.