Sarcomatoid carcinoma of the renal pelvis in duplex kidney

Sarcomatoid transitional cell carcinoma of the renal pelvis is a rare neoplasm with only 14 well-illustrated examplesreported previously. Duplex kidney is the most common congenital abnormality of the urinary tract, with an incidence ofaround 2%. Neoplasia of the renal pelvis in duplex kidney is rare. We reported a case whose sarcomatoid carcinomaoriginated from the upper portion of the duplicated renal pelvis with hydronephrosis, and total nephroureterectomy withbladder cuff excision surgery of both renal units was carried out. Because of the rare nature of renal pelvic sarcomatoidcarcinoma and its apparent lack of response to adjuvant therapy, it is essential to do early diagnosis and early radicalsurgery to improve survival. It is important to stress the need for frequent and diligent monitoring or treating complexduplex kidney with hydronephrosis of either moiety in case of a risk of having neoplasias.