Xanthogranulomatous pyelonephritis: a case with rare adhesion to pancreas

Abstract

Xanthogranulomatous pyelonephritis (XGP) is a rare benign condition with unknown aetiology and chronic infection of kidney. Commonly, most cases are related with urinary tract obstruction, nephrolithiasis, infection, diabetes, and/or immune compromise. XGP is associated with destruction of the renal parenchyma and granulomatous inflammation with foamy lipid-laden macrophages resulting from obstructive uropathy. It closely mimics a malignancy, exhibiting local tissue invasion and destruction. Adjacent organs especially duodenum as well as very rarely pancreas or spleen may be involved. Additionally, XGP is known as notorious for fistulisations, such as pyelocutaneous and ureterocutaneous fistulae, which have been reported as well described. XGP may be indistinguishable from renal cell carcinoma by radiographic and clinic consultation so it must be diagnosed based on the histopathologic examinations. Furthermore, macroscopic appearance of XGP is a mass of yellow tissue with focal haemorrhage besides necrosis and in this regard, it grossly resembles renal cell carcinoma. Here, we report the case of a 32-year-old female, preoperatively diagnosed as malignancy by clinical examination. Our further pathological evaluations revealed very rarely adhesion of XGP to pancreas tissue.

Xanthogranulomatous pyelonephritis in a child – a case report

“…The current classification distinguishes between 3 stadia of XGP: I: confined to the affected kidney, II: involving the renal fascia (Gerota's fascia), and III: extending into the perinephric space (6) . The final diagnosis almost always requires surgical inspection and histopathological examination.…”

“…Due to technical difficulty and potential complications, laparoscopy is not recommended. There are only several reports regarding laparoscopic procedures, and long-term outcomes have not been studied (6) .…”

Xanthogranulomatous Pyelonephritis: A Narrative Review with Current Perspectives on Diagnostic Imaging and Management, Including Interventional Radiology Techniques

“…The degree of extra-renal extension can be profound, with reported cases of pancreatic, splenic and hepatic infiltration with abscess formation, cutaneous, colonic and duodenal fistulae and rib osteomyelitis also described. [10][11][12][13][14][15] Very rare instances of renal amyloidosis secondary to XGP have been reported. 16-18.…”

“…Extra-renal extension including collections and fistulae are well depicted on CT, which permits demarcation of the extent and boundaries of the inflammatory process, determining if it is confined to the kidney (focal/segmental or disseminated) (Figure 5) and, in the presence of extrarenal extension, if it is confined to the perinephric or pararenal spaces and/or if it infiltrates adjacent tissues and viscera. [10][11][12][13][14][15] A case series of 11 patients with XGP found that 10 patients (91%) had extra-renal extension, three of whom (27%) had direct extension into adjacent structures including iliopsoas muscle, abdominal wall and spleen. 37 CT facilitates staging as per Malek et al as follows: 26 Stage 1: Confined to renal parenchyma.…”

“…Complications such as infiltration of the pancreas, spleen and liver with secondary abscess formation, cutaneous and colonic fistulae as well as rib osteomyelitis are all elegantly demonstrated by CT (Figure 6). [11][12][13][14][15] The main differential diagnosis for the CT appearances of XGP is primary renal malignancy; the presence of a Bear-Paw sign, a staghorn calculus and extrarenal extension of inflammation can help to differentiate XGP from primary renal malignancy. Although these are the characteristic imaging features of XGP, there is variability in their presence as described above; thus, while XGP may be the primary differential on CT, this often requires pathologic confirmation, given the significant overlap of findings with other conditions such as pyelonephritis, tuberculosis, malakoplakia and megalocytic interstitial nephritis.…”