Renal cell cancer and concomitant transitional cell cancer of the renal pelvis and ureter in the same kidney--report of 4 cases and review of the literature.

Three patients (1 man, 81 years old; 2 women, 56 and 61 years old) had renal cell cancer and transitional cell cancer in the same kidney, and another patient (female, 77 years old) had renal cell cancer and transitional cell cancer in the ipsilateral ureter. Simultaneous occurrence of renal cell cancer and transitional cell cancer is an extremely rare entity with only 15 cases having been reported.