GENITOURINARY IMAGING: Collecting System, Ureter, Bladder
Case Author: Rupan Sanyal, MD, University of Alabama at Birmingham
History
48-year-old man with 3 months of fever and persistent right flank pain.
Imaging Findings
Axial contrast-enhanced CT image (A) shows a dilated upper right renal calyx with a focus of gas (arrow). Axial CT image (B) caudal to A shows renal pelvic calculi and an irregular nonenhancing low-attenuation area in the posterior aspect of the kidney with perinephric extension.
Initial percutaneous nephrostogram (C) shows dilated right renal calyces. Image after injection of additional contrast medium (D) shows opacification of the duodenum (arrows).
Diagnosis
Pyeloduodenal fistula due to xanthogranulomatous pyelonephritis
Teaching Points
Xanthogranulomatous pyelonephritis (XGP) is an unusual variant of chronic pyelonephritis that results in granulomatous destruction of the kidney. Nephrectomy of the nonfunctioning kidney is the treatment of choice.
Longstanding infection and renal obstruction cause XGP. Renal stones are present in most cases.
Fistula formation to the skin and adjacent organs, such as the duodenum, is characteristic of XGP.
Focal renal abscess formation also occurs.
Histopathologically, lipid-laden macrophages are characteristic of XGP.
Suggested Readings
Craig WD, Wagner BJ, Travis MD. Pyelonephritis: radiologic-pathologic review. RadioGraphics 2008; 28:255–277
Hayes WS, Hartman DS, Sesterbenn IA. Xanthogranulomatous pyelonephritis. RadioGraphics
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