Xantogranulomatous pyelonephritis: The missed diagnosis

INTRODUCTION: Xantogranulomatous pyelonephritis (XGPN) is a rare chronic inflammatory disease of the kidney that can be focal or diffuse with the focal form imitating greatly renal cell carcinoma (RCC). PRESENTATION OF CASE: We report a challenging clinical case of a 38-year old male with right flank pain persisting for 3-months, imaging showed an 8 cm heterogenous mass of the upper pole of the right kidney and invading the liver. A right radical nephrectomy including the adrenal in the resection was performed under the tentative diagnosis of renal cell carcinoma (RCC) whereas histology revealed focal XGPN. DISCUSSION: Preoperative diagnosis of focal XGPN was difficult because of radiological similarities to RCC and lack of history of stone disease or urinary tract infection. CONCLUSION: This case highlights the need to include XGPN in the differential diagnosis of RCC even in the era of modern imaging.