Xanthogranulomatous pyelonephritis: clinical, radiological and pathologic characteristics

Xanthogranulomatous pyelonephritis is an atypical chronic infection which simulates a malignant renal neoplasia, definitive diagnosis of which is obtained by pathologic study after surgical removal. In this paper we analyze our experience and compare it to that reported on the literature. We performed a retrospective study of cases of xanthogranulomatous pyelonephritis diagnosed in the period from January 1945 to December 2000 at the Institute of Neoplastic Diseases, analyzing clinical, radiological, and surgical features documented in the medical records. There were 11 cases, 82% of them were females. The presence of signs and symptoms such as pain and abdominal mass appeared in 73%, accompanied by hematuria and fever. Most radiological tests showed destruction of the renal parenchyma with abnormalities in the collecting system and obstruction by lithiasis. 91% of the cases had positive urine cultures, being Escherichia coli, Proteus Mirabilis and Klebsiella the most frequent germs. Simple nephrectomy was the surgical treatment, and complications were minimal. Xanthogranulomatous pyelonephritis should be considered in the differential diagnosis of renal cancer because of its clinical features.