[Xanthogranulomatous pyelonephritis with phlegmonous abdominal wall infiltration. Diagnosis and assessment of extent...

A 34-year-old woman who 14 years previously had undergone a left nephrotomy for nephrolithiasis complained of pain in the left renal fossa which was reddened and painful on percussion. She had a fever of 38.2 degrees C. C-reactive protein was raised to 80 mg/l, the white cell count to 14,620/microliters (83% neutrophils). Protein and white cells were found in the urine together with a significant number of E. coli on urine culture. Plain film of the abdomen showed a staghorn calculus and ultrasonography demonstrated renal enlargement with a possible paranephritic abscess. The computed tomography diagnosis was xanthogranulomatous pyelonephritis, on the basis of renal enlargement, staghorn calculus, hypodense areas with typical density values (10-15 Hounsfield units), contrast enrichment and extrarenal extension of partly phlegmonous partly fused-together inflammatory changes. The abscessing parts were drained under computed tomography control. Starting 7 days pre-operatively the patient had been receiving ciprofloxacin (0.4 g daily) intravenously. A nephrectomy had to be performed subsequently. Antibiotic treatment was discontinued 2 weeks later and she was discharged symptom-free. The diagnosis of diffuse xanthogranulomatous Pyelonephritis was confirmed by histological examination of the surgical specimen.