An unusual case of xanthogranulomatous pyelonephritis in a leukemia patient.

We report a 65-year-old woman with leukemia who presented with urinary tract infection, splenic abscess, and a renal mass. Both urine and pus culture of the splenic abscess yielded Klebsiella pneumoniae. The differential diagnosis of the renal mass by radiological findings included unliquefied renal abscess, xanthogranulomatous pyelonephritis, and renal cell carcinoma. Percutaneous biopsy of the renal mass confirmed the diagnosis of xanthogranulomatous pyelonephritis. Because of high surgical risk, the patient received medical treatment with prolonged antibiotic therapy. With antibiotic therapy only, not only the splenic abscess was cured but also follow-up ultrasonography showed progressive resolution of the renal mass. The occurrence of xanthogranulomatous pyelonephritis has rarely been reported in the absence of urinary tract obstruction or nephrolithiasis. Furthermore, this is the first report of xanthogranulomatous pyelonephritis occurring in patients with leukemia and concurrent with splenic abscess. In addition to describing this unusual case, we provide a short review of xanthogranulomatous pyelonephritis successfully treated with antibiotics only.