Xanthogranulomatous pyelonephritis: Our experience with review of published reports

Background: The aim of this study was to analyse the cases of xanthogranulomatous pyelonephritis with review of published reports. Methods: We retrospectively reviewed all nephrectomy specimens during February 1995 to January 2006. We found 26 cases of xanthogranulomatous pyelonephritis. We prepared a chart of these cases consisting of preoperative symptoms, laboratory findings, radiological imaging results and preoperative diagnosis. Open nephrectomy was carried out in all cases. Results: Age group of the patients was 6-65 years and male : female ratio was 1.6:1. Twenty-two patients presented to us with intermittent high-grade fever, 21 with flank pain, 18 with loin mass, 2 with haematuria and 1 was detected during screening of vague gastrointestinal symptoms. Twenty-five patients had pyuria and only 10 had sterile urine culture. In all patients, only one kidney was affected. All patients had renal calculi 10-42 mm in size with bilaterally enlarged kidneys. Ipsilateral kidney was enlarged because of hydronephrosis or pyonephrosis in all cases and contralateral kidney was enlarged because of compensatory hypertrophy in 13 cases. Ipsilateral kidney had severely compromised renal function in all cases. Associated psoas abscess was present in one and tuberculosis in another. Conclusion: Xanthogranulomatous pyelonephritis is a relatively rare entity that is associated with obstruction, stones and infection of the urinary tract. Late presentation leads to loss of renal parenchyma. It cannot be differentiated preoperatively with renal tumours (renal cell carcinoma and Wilms' tumour), pyonephrosis, infected hydronephrosis and renal lymphoma. Nephrectomy and antibiotics are the treatment of choice.