Xanthogranulomatous pyelonephritis radiology

Atypical, incomplete immune response to subacute bacterial infection
10% with DM

Presentation
• Low-grade fever, malaise
• Flank pain, hematuria
• 9% with pyuria, 60% urine culture(+)
• More frequent in women in 45-65 years old

Pathology
– Parenchyma replaced with lipid-laden macrophages
– Associated with renal pelvic calculus, hydronephrosis
➜ Lamellated staghorn stone

IMAGING
– Non-functioning enlarged kidney
; Absent nephrogram (no enhancement)
– Central calculus(staghorn stone) with contracted pelvis, calyceal expansion
– Extensive inflammatory change may mimic fluid or hydronephrosis
– Inflammatory change of perirenal fat
– 90% diffuse
– 10% focal form
; mimic bacterial abscesss, neoplasm

TREATMENT
– Nephrectomy usually required
– Good prognosis

Reference)
A Kawashima. RadioGraphics 1997; 17: 851-566
WD Craig. RadioGraphics 2008; 28: 255-276

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