Primary urinary bladder tumors in three guinea pigs (Cavia porcellus).

Urinary bladder tumors are not common in guinea pigs, but case numbers being diagnosed have increased in the past years. The authors present three referred cases of primary urinary bladder tumors in pet guinea pigs diagnosed using diagnostic imaging (CT, radiography and ultrasonography) and exploratory laparotomy. Excision was not possible in the first case as the tumor was located at the neck of the urinary bladder and the owner opted for intraoperative euthanasia. The second and third cases both had tumors originating from the apex of the urinary bladder. The third guinea pig went into cardiac arrest during surgery and resuscitation was unsuccessful. The tumor was removed from the urinary bladder using partial cystectomy in the second case and one-month post-surgery ultrasonographic examination showed no signs of tumor reoccurrence. Late recognition is the main reason for a negative outcome, as by this time tumors are already large and extensive. Whenever prolonged symptoms of hematuria are present and urolithiasis has been ruled out, ultrasonography should be undertaken to determine if a urinary tumor is the cause. Rechecks should be scheduled on a regular basis for guinea pigs when a definitive diagnosis cannot not be made at initial presentation for vague clinical signs, as outcome and survival can reduce significantly when definitive treatment is delayed.