Focal Xanthogranulomatous Pyelonephritis on FDG PET/CT

Area of Science:

• Nephrology
• Radiology
• Pathology

Background:

• Xanthogranulomatous pyelonephritis (XGP) is a rare, chronic inflammatory kidney disease.
• Focal XGP often presents diagnostic challenges, frequently being misdiagnosed as renal malignancy.

Observation:

• This report details a 66-year-old woman with polycystic liver and kidney disease presenting with focal XGP.
• FDG PET/CT imaging revealed a cystic mass in the right kidney's inferior pole with high FDG uptake in the cystic wall.

Findings:

• The imaging findings were initially suggestive of cystic renal carcinoma.
• Post-surgical pathological examination confirmed the diagnosis of xanthogranulomatous pyelonephritis.

Implications:

• FDG PET/CT findings in focal XGP can mimic malignancy, underscoring the importance of integrating imaging with clinical and pathological data.
• Accurate diagnosis of XGP is crucial for appropriate management and avoiding unnecessary radical surgeries.