[Xanthogranulomatous pyelonephritis combined with retroperitoneal xanthogranuloma, simulating kidney tumor]

Xanthogranulomatous pyelonephritis is a special variant of interstitial nephritis, when an inflammatory infiltration contains xanthomatous cells. Its diagnosis is difficult and possible only on the basis of a histologic analysis of a surgically removed kidney. A case of xanthogranulomatous pyelonephritis combined with retroperitoneal xanthogranuloma is presented. Kidney carcinoma was suspected and in the course of operation the biopsy of kidney was taken. In the authors' opinion a histologic express diagnosis is recommended during the operation.