Xanthogranulomatous Pyelonephritis—Mimicking Renal Mass in 5-Month-old Child

Xanthogranulomatous pyelonephritis mimicking a renal cell carcinoma: a unique and challenging case

“…It is clearly related to a combination of renal obstruction and chronic bacterial infection and usually occurs in association with nephrolithiasis, urinary tract obstruction, and chronic urinary infection (12,13). Other causes of obstruction include congenital abnormalities such as uretero-pelvic junction obstruction and tumors that occur mainly in the adult population (renal cell carcinoma, ureteral carcinoma, bladder carcinoma) (11,14). Other factors implicated in the etiology of XGPN include altered immune response and intrinsic disturbance of leukocyte function, alterations in lipid metabolism, lymphatic obstruction, malnutrition, arterial insufficiency, venous occlusion and hemorrhage, and necrosis of the pericalyceal fat (3,9,11,14,15).…”

“…Other causes of obstruction include congenital abnormalities such as uretero-pelvic junction obstruction and tumors that occur mainly in the adult population (renal cell carcinoma, ureteral carcinoma, bladder carcinoma) (11,14). Other factors implicated in the etiology of XGPN include altered immune response and intrinsic disturbance of leukocyte function, alterations in lipid metabolism, lymphatic obstruction, malnutrition, arterial insufficiency, venous occlusion and hemorrhage, and necrosis of the pericalyceal fat (3,9,11,14,15). The most commonly reported symptoms are fever, abdominal and/or flank pain, weight loss, malaise, anorexia, and lower urinary tract symptoms.…”

Xanthogranulomatous pyelonephritis presenting as a pseudotumour in a 5-year-old boy

“…Two forms of XGPN have been described, a diffuse or global form (84.6%) as is this case, and a focal form (15.4%) 1 4 10 16. It is further classified into three stages: stage I, the lesion is confined to the kidney (nephric), stage II, when it extends to Gerota's space as is this case (perinephric) and stage III, the extension to the perinephric space or retroperitoneal structures (paranephric) 4 10…”

“…Other factors have also been implicated and include altered immune response and intrinsic disturbance of leucocyte function, alterations of lipid metabolism, lymphatic obstruction, malnutrition, arterial insufficiency and venous occlusion 4 10 16…”

“…Distinctive ultrasound and CT appearances of XGPN have been reported 1 3 9 11 16 18–20. Ultrasound of diffuse XGPN usually shows an enlarged kidney with a large amorphous central echogenicity that corresponds to renal pelvis staghorn calculus, irregular thinned parenchyma, dilated collecting system and multiple hypoechoic fluid-filled masses.…”