[A case of xanthogranulomatous pyelonephritis probably derived from a renal injury]

A 56-year-old women was admitted for examination of glycosuria. She had had a blunt trauma onto the left abdomen 2 years ago that could have caused renal injury. Incidentally a left renal mass was detected by ultrasonography as a low echogenic mass. CT scan revealed a 2.5 X 2.5 cm mass with lower density than the kidney. IVP and renal angiography showed no abnormal findings. Under the diagnosis of renal tumor, left nephrectomy was performed. A 2 X 2 cm butter-yellow tumor, was seen in the renal parenchyma including the renal capsule of the upper and lateral part of the kidney. The renal pelvis was normal and there were no suppurative lesions in the kidney. Histopathological diagnosis was xanthogranuloma of the kidney partly containing a subcapsular hematoma. The previous blunt trauma, presence of hematoma and no evidence of suppurative lesions suggested that the etiology of xanthogranuloma in this case was related to renal injury.