Ultrasonography & Cystoscopy

A 5-year-old, 34.4-kg spayed dog was presented with subacute hematuria and stranguria that did not resolve after a 14-day course of ciprofloxacin. On ultrasound, an irregular 2.75 × 4.79-cm mass was found in the cranioventral aspect of the urinary bladder. The dog was sedated, and a 41-cm, 10-Fr rubber catheter with the blind end cut off was passed into the urethra. The patient was then placed in dorsal recumbency and saline infused through the urinary catheter to distend the bladder. The rubber catheter was advanced via ultrasound guidance and was aligned with the bladder mass. Flexible wire ellipsoid cup biopsy forceps (190 mm × 1.8 mm) were threaded through the rubber catheter until they were visualized exiting the catheter. The forceps and catheter were advanced as a unit, and a biopsy was obtained. The biopsy forceps were withdrawn from the rubber catheter to retrieve the biopsy sample and the process repeated to obtain multiple biopsies. There were no complications, and the patient was discharged several hours later. Histopathology was consistent with polypoid cystitis. The polyp was surgically removed, and histopathology confirmed the diagnosis. The authors conclude that this technique is a noninvasive option for obtaining urinary bladder mass biopsies, especially when general anesthesia is contraindicated or cystoscopy is not available. Limitations include lack of direct visualization, risk for hemorrhage, and patient size.

Commentary

This is an ingenious solution to a common problem. Ultrasonography is becoming a frequently used tool in general practice but is also readily available on a referral basis. Lesion location is likely the biggest limitation because the catheter follows a pretty standard path. The size and material the biopsy forceps are made from could also cause instrument artifacts affecting visualization, but this was not an issue in the case presented. Cystoscopy, while allowing direct visualization, has its own limitations and requires a variety of scopes depending on the size and gender of the patient. As the procedure can be done in the awake or sedated patient, it could be an excellent first choice with cystoscopy as a backup if unsuccessful.—Eric R. Pope, DVM, MS, DACVS