Xanthogranulomatous pyelonephritis associated with transitional cell carcinoma of the renal pelvis.

Xanthogranulomatous pyelonephritis (XPN) is an uncommon, but not rare, type of bacterial infection of the kidneys. Malignancies originating within the renal pelvis are uncommon. We report a case of XPN associated with a transitional cell carcinoma (TCC) of the renal pelvis in a 70-year-old woman. The pathogenesis of carcinoma of the renal pelvis in the presence of XPN is related to obstruction, chronic inflammation, and mechanical irritation caused by calculi. In the case reported here, obstruction was due to a concomitant TCC of the ureter without the presence of calculi. A review of the twelve published case reports of XPN with TCC of the renal pelvis, including the present case, showed that the frequency of this association is 3.3%, the average age at presentation is 65.3 (range 49-78) years, and that the male:female ratio is 2:1. Moreover, 25% of the patients had TCC of the ureter and 8.3% TCC of the bladder. The combination of XPN, TCC of the renal pelvis, and lithiasis occurred in 33.3% of the cases. XPN must be treated by nephrectomy not only because it is a destructive inflammatory process leading to complete loss of renal function, but also because the kidney may be harboring a malignant tumor.