Urethral polyps are found with a cystoscope. A cystoscope is a long, thin telescope with a light at the end that lets your urologist look inside the body. In children this is usually performed in the operating room under anesthesia. However, the key test to diagnosing benign urethral lesions is a voiding cystourethrogram (VCUG). VCUG is a type of x-ray test. VCUG uses a special dye infused into the urethra to show the structures.