Clinicopathological study of upper urinary tract tumors associated with bladder tumors

Among 535 cases of urothelial tumors (upper urinary tract and bladder tumors) from 1970 to 1988, 40 had upper urinary tract tumor associated with bladder tumor. Of 40 cases, 18 (45%) were synchronous, 17 (43%) were metachronous with primary upper urinary tract tumor followed by subsequent bladder tumor 18.5 +/- 14.1 (means +/- SD) months later and 5 (12%) were metachronous with primary bladder tumor followed by subsequent upper urinary tract tumor 40.2 +/- 13.6 months later. The incidence (17/52 = 0.32) of bladder tumor occurrence subsequent to primary upper urinary tract tumor was much higher than that (5/465 = 0.01) of upper urinary tract tumor subsequent to primary bladder tumor. The histologic grades of upper urinary tract tumor and associated bladder tumor were consistent in 73%. Except in 1 case, multiple occurrence of upper urinary tract tumor was always observed unilaterally on the side involved. The current results not only support the theory of multicentricity but raise the possibility that tumor cell implantation may play some role at least in the development of bladder tumor subsequent to upper urinary tract tumor.