Abstract
Xanthogranulomatous pyelonephritis (XP) is a rare form of pyelonephritis and without treatment destructive to the kidney. We describe a 74-year-old Caucasian immunocompetent female patient with XP and multiple abscesses on the upper pole of the right kidney and several impacted obstructing renal calculi in the middle calyx that developed severe colitis and gangrenous appendicitis during therapy. Proteus mirabilis was detected as the major pathogen in the urine culture. Kidney preserving therapy was carried out by intensive parenteral bacterial eradication, CT-guided abscess drainage and stone destruction by 3 sessions of extracorporeal shock wave lithotripsy under ureteral stenting. Large tumor masses in XP are often daunting and may lead to a nephrectomy. However, kidney-preserving therapy is possible and should be considered in non-septic patients or in case of a solitary kidney.