My partner and I had a similar patient that presented with a large kidney tumor that was growing into the renal pelvis and ureter. We performed a ureteroscopy and the tumor appeared as a large bulge growing down the ureter that reminded me of renal cancer growing into the renal vein. A biopsy came back as benign urothelium.
On these rare cases, I have developed a protocol to perform a robotic radical nephrectomy and transect the ureter by stapling it. I obtain pathological analysis at the time of surgery, and if the diagnosis is transitional cell cancer, I proceed to remove the rest of the ureter and a bladder cuff with robotic surgery at the same time.