Discussion of Xanthogranulomatous pyelonephritis
- Xanthogranulomatous pyelonephritis (XGP) is a rare inflammatory condition usually secondary to chronic obstruction caused by nephrolithiasis and resulting in infection and irreversible destruction of the renal parenchyma.
- XGP is associated with a staghorn calculus in approximately 70% of cases.
- Patients with diabetes are particularly predisposed to the formation of XGP.
- Treatment is with nephrectomy.
- At histologic analysis, the inflammatory mass is composed of lipid-laden macrophages and chronic inflammatory cells.
 Imaging Findings of Xanthogranulomatous pyelonephritis
- Classic urographic triad in diffuse xanthogranulomatous pyelonephritis consists of unilaterally decreased or (more commonly) absent renal excretion, a staghorn calculus, and a poorly defined mass or diffuse renal enlargement.
- At sonography, the inflammatory mass itself is hypoechoic, with central echogenic foci corresponding to renal calculi.
- The CT findings of xanthogranulomatous pyelonephritis are pathognomonic in most cases: diffuse reniform enlargement with ill-defined central low attenuation, apparent cortical thinning, and central calculi.
- Extension into the perinephric space and beyond the Gerota fascia is not uncommon.
- Central areas of low attenuation represent nonenhancing xanthomatous material that may demonstrate attenuation values less than those of water.
Patient #1: CT images demonstrate right xanthogranulomatous pyelonephritis
 See also
 External Links
- Bhatt, Shweta, MacLennan, Gregory, Dogra, Vikram. Renal Pseudotumors. Am. J. Roentgenol. 2007 188: 1380-1387.
- Perry J. Pickhardt, Gael J. Lonergan, Charles J. Davis, Jr, Naoko Kashitani, and Brent J. Wagner. From the Archives of the AFIP : Infiltrative Renal Lesions: Radiologic-Pathologic Correlation. RadioGraphics 2000 20: 215-243.