[A Case of Urothelial Carcinoma of Renal Pelvis Intraoperatively Diagnosed during Robot-Assisted Ureterocalicostomy].

A female in her sixties with a history of pyelolithotomy for right kidney stone at age 26 presented with right back pain. Computed tomography of the abdomen showed right hydronephrosis,and a retrograde pyelogram showed stenosis of the pelviureteric junction. Five years after initial presentation, robot-assisted renal ureterocalicostomy was planned for recurrent back pain, and decreased renal function. The lower renal calix was exposed and anastomosis with the ureter was performed for half of the caliceal hole. However, intraoperative flexible endoscopy, which was performed to confirm the position of the repositioned stent, revealed a papillary tumor in the upper renal calix. The patient underwent nephroureterectomy upon diagnosis of renal pelvic urothelial carcinoma.