AB160. SOH22ABS167. An unusual presentation of xanthogranulomatous pyelonephritis: discharge sinus of iliopsoas abscess fistula

Background: Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis characterized by being a chronic destructive granulomatous inflammation of the renal parenchyma with an accumulation of lipid-laden fibrous tissue, and acute and chronic inflammatory cells. XGP is classified according to the extent of disease into focal or segmental XGP of the renal cortex or diffuse XGP with pelvic communication. It may involve any organ, but the most common sites are known as the gallbladder and kidney, lower GI tract. Although rare, XGP can have fatal complications including perinephric, psoas abscess, nephrocutaneous fistula, and reno-colic fistula. Only a few studies have reported XGP complicated with psoas abscess.

Methods: We report a case of a 75-year-old woman who presented with a large left groin abscess with discharge sinus on the anterior abdominal wall, therefore she was admitted under general surgery. She had a history of appendectomy for pseudomyxoma. CT showed the edematous appearance of left kidney with staghorn calculus and bear paw sign suggestive of XGP with marked pyonephrosis, secondary to left psoas and iliopsoas collections extending into the left groin and communicating with skin surface with passage of renal calculus into left groin collection.

Results: She was managed by IV antibiotic, nephrostomy, surgical abscess drainage, and subsequent nephrectomy.

Conclusions: We aim to add to the literature and share our experience with a rare case of extensive XGP presented as discharge sinus iliopsoas abscess leading to severe sepsis which was managed successfully.

Keywords: Xanthogranulomatous pyelonephritis (XGP); sinus iliopsoas abscess; reno-colic fistula; perinephric; chronic destructive granulomatous inflammation