Mapping of urothelium in carcinomas of the renal pelvis and ureter: A report of nine cases

Complete histologic mapping of the urothelium was performed in nine surgical nephroureterectomy specimens. In seven patients, the primary lesion was carcinoma of the renal pelvis; in two, carcinoma of the ureter. In all cases, in areas peripheral to obvious carcinomas, there were extensive epithelial abnormalities akin to those previously described in mapping studies of the urinary bladder. The epithelial changes ranged from hyperplasia to flat carcinoma in situ. The latter was observed in four patients and appears to be an unfavorable prognostic sign: one of the four patients died of disease three months after surgery, and two patients developed metachronous carcinomas of the urinary bladder. Only one of these four patients has been free of disease for 21 months. One additional patient with atypical urothelium in the renal pelvis also developed a metachronous bladder cancer. Significant neoplastic abnormalities of the epithelium of the collecting ducts were observed in six of the seven cases of carcinoma of the renal pelvis. The study emphasizes the essential unity of the urothelium as a target organ for neoplastic events.