FDG PET/CT and MRI findings in a patient with focal xanthogranulomatous pyelonephritis mimicking cystic renal malignancy.

Focal xanthogranulomatous pyelonephritis (XGP) is a chronic inflammatory condition that can mimic other disease conditions such as pyelonephritis, tuberculosis, renal abscess, renal cell carcinoma, and renal metastasis. Urinary tract infection and obstruction are considered to be predisposing factors. The clinical symptoms and imaging findings are often nonspecific so that an incorrect initial diagnosis is common. Here, we report a case of a patient with focal XGP with FDG PET/CT findings that mimic renal malignancy.