Coexistence of Massive Renal Replacement Lipomatosis With Focal-type Xanthogranulomatous Pyelonephritis in the Same Transplanted Kidney on FDG PET/CT

Here we present the FDG PET/CT findings of a case of coexistence of renal replacement lipomatosis and xanthogranulomatous pyelonephritis in a 62-year-old man with a history of renal transplantation. The image showed an enlarged transplanted kidney with marked fatty proliferation within the renal sinus and hilum with heterogeneous mild FDG uptake, and a cystic nodule in the inferior pole with high FDG uptake in the cystic wall, suggesting an infection. The final pathologic diagnoses of these two lesions were renal replacement lipomatosis and xanthogranulomatous pyelonephritis, respectively.