Pathologic Classification by Intraductal Involvement and Parenchymal Invasion of Transitional Cell Carcinoma in the Renal Pelvis

Lee, Chang Soo; Lee, Nam Kyu; Park, Young Ho

Abstract

Transitional cell carcinomas in the renal pelvis account for approximately 5 to 10 per cent of all renal tumors and about 5 per cent of all urothelial tumors. Transitional cell carcinoma can arise anywhere in the urinary tract, from the renal pelvis to the distal urethra, and has developmental characteristics of invading the `muscle layer as well as spreading to the contiguous or noncontiguous urothelial surface. Renal pelvic cancer extending into collecting duct may exhibit different biological behavior because there is no degradation or penetration of the basement membrane. Usually renal parenchymal invasion of renal pelvis tumor has been classified as stage pT3. Whether tumor involvement within the collecting ducts should be classified as parenchymal invasion is not clear in TNM/pTNM classification. We have classified 15 patients of renal pelvic TCC on the side of renal parenchyma; Type I) 3 tumors involving the collecting ducts without invasion of renal parenchyma, Type II) 4 tumors involving the collecting ducts with microscopic invasion of renal parenchyma, Type III) 3 tumors involving the renal parenchyma by less than 5mm without ductal involvement, Type IV) 5 tumors invading extensive renal parenchyma and studied biologic behavior. Our results showed that the renal pelvic TCC patients with intraductal extension showed favorable prognosis than those with renal parenchymal invasion. The number of patients in our study is small. So further studies are necessary to elucidate the clinicopathological significance of the developmental pattern of renal pelvic cancer.