Xanthogranulomatous Pyelonephritis

Figure 1. An 86-year-old woman with a several-year history of recurrent urinary tract infections presented with vague abdominal symptoms. Physical examination disclosed right-flank tenderness. She had an Escherichia coli urinary tract infection. A contrast-enhanced computed tomographic (CT) scan, obtained because the findings on ultrasonography and radiography were inconclusive, showed typical findings of xanthogranulomatous pyelonephritis in the right kidney (Panel A). This chronic bacterial infection of the kidneys is characterized by the destruction of renal parenchyma and the presence of granulomas, abscesses, and cellular infiltrates of lipid-laden macrophages (foam cells). Multiple masses (M) replaced the renal parenchyma and extended into the . . .