Bilateral Xanthogranulomatous Pyelonephritis With Renocolic and Duodenal Fistulas

Xanthogranulomatous pyelonephritis (XGP) is an uncommon destructive inflammatory disease of the kidney associated with chronic urinary obstruction, calculi, and infection.Bilateral disease is exceptionally uncommon and creates a particular therapeutic problem because definitive nephrectomy may compromise native renal function.We describe a 65-year-old man with chronic kidney disease and recurrent nephrolithiasis who presented with shortness of breath and severe microcytic anemia without prominent urinary symptoms.Serum creatinine was 4.67 mg/dL, increased from prior values of approximately 1.3-1.8mg/dL.Imaging demonstrated bilateral staghorn calculi, marked parenchymal destruction, and characteristic bear-paw morphology, with more extensive disease on the right.Bilateral nephrostomy tubes were placed for decompression, after which serum creatinine improved to approximately 3 mg/dL.Repeat CT demonstrated persistent bilateral disease, multiple right perirenal fluid-and gas-containing collections, and a fistula between an abscess anterior to the right kidney and the proximal transverse colon.The patient subsequently underwent right nephrectomy, during which a duodenal fistula was also identified.Histopathologic rereview demonstrated lipid-laden foamy macrophages with suppurative inflammation, confirming XGP.Left nephrectomy was deferred at the patient's request.This case highlights a systemic presentation of advanced bilateral XGP without prominent urinary symptoms, its potential for enteric fistulization, and the need to balance definitive source control against preservation of native renal function.