The role of microscopic hematuria in the evaluation of urologic malignancy in renal transplant recipients.

Urologic malignancy is a relatively uncommon but serious complication following kidney transplantation. The reported prevalence of renal cell carcinoma (RCC) of the native kidneys is 4.4% and of bladder malignancy is 2.6%. However, presently there are no universal guidelines for prospective screening of urologic malignancies after kidney transplantation. We routinely monitored all renal transplant recipients for microscopic hematuria and persistent hematuria (>3 separate occasions) results in imaging studies (ultrasound or computed tomography scan) of both native kidneys and the allograft. Cystoscopy is performed if imaging studies are negative. This retrospective study identified a total of 18 urologic malignancies among the study cohort, which consisted of 539 patients with an incidence of 3.3% (12 cases of RCC of native kidneys [10/12 had hematuria], and six cases of bladder and ureteral malignancies [6/6 had hematuria]). There were no significant differences between cyclosporine- and tacrolimus-based immunosuppression (IS). Among RCC recipients, two lost the allograft from chronic allograft nephropathy and one patient died unrelated to malignancy. Among patients with bladder and ureteral malignancies, two lost the graft possibly from IS reduction and one had BK virus nephropathy prior to diagnosis of bladder carcinoma. In conclusion, screening transplant recipients routinely for persistent microscopic hematuria may identify urologic malignancies in renal transplant recipients.