[A clinical study of xanthogranulomatous pyelonephritis (XGP) with special emphasis on the magnetic resonance imaging].

Xanthogranulomatous pyelonephritis (XGP) is an uncommon form of granulomatous inflammation characterized by destruction and replacement of the renal parenchyma by masses of lipid-laden macrophages. We report the first case of the pyonephrotic type of XGP in which Magnetic resonance imaging (MRI) was used in Japan, and summarize the clinical characteristics of 163 cases with XGP in the Japanese literature for age, sex, laboratory data, preoperative diagnosis and operation. A 56-year-old female was admitted with left flank pain. Left nephrectomy was performed following diagnosis of XGP by computed tomography (CT) and MRI. Histopathological findings confirmed the diagnosis of XGP. Furthermore, we evaluated the MR images in XGP. MR images correlated well with the CT images showing an enlarged multiloculated kidney. The internal portion of the loculated areas were of intermediate intensity on T1-weighted images, and became very intense on the T2-weighted sequences, indicating a long T2. MRI appears to be of value in the investigation of renal mass lesions.