BCGosis: case report of intravesicular bacille Calmette-Guérin causing upper tract granulomas simulating a renal mass without evidence of ipsilateral vesicoureteral reflux.

Very rarely, dissemination of intravesical bacille Calmette-Guérin for superficial bladder cancer treatment can lead to a complication in the upper urinary tract. Two mechanisms for dissemination have been proposed: vesicoureteral reflux and hematogenous spread. We report a case of "BCGosis" with the clinical appearance of multifocal renal masses in a patient without ipsilateral reflux. This case highlights the importance of obtaining a renal biopsy in all patients previously treated with bacille Calmette-Guérin presenting with a renal mass. Furthermore, the findings from the present case suggest that vesicoureteral reflux might not be the only mechanism responsible for dissemination of bacille Calmette-Guérin to the upper urinary tract.