Association of xanthogranulomatous pyelonephritis with small renal cell carcinoma. Case report and review of the literature.

A case of xanthogranulomatous pyelonephritis associated with 'small' renal carcinoma is presented. The urinary sediment showed atypical cells, suspect of malignancy. The renal neoplasm measured only 1.5 cm, had the typical papillary configuration of a 'small' renal carcinoma and was composed of atypical cells with finely granular cytoplasm and hyperchromatic nuclei. The xanthogranulomatous pyelonephritis was a primary lesion, spacially separate one from the other. The clinicopathological features of reported examples of coexistence of these diseases have been reviewed.