<prompt> Sheela, a middle aged diabetic female presented with flank pain and fever. On US the kidney was irregular and showed fat density with calculi. The diagnosis is most probably:TB kidneyXanthogranulomatous kidneyChronic pyelonephritisRenal abscess  <response>: Ans. b Xanthogranulomatous kidneyRef: Smith 17th Edition, Pages 204-206; Campbell 10th Edition, Page 308Xantho Granulomatous pyelonephritis XGP Xantho means lipid foam cells Xanthogranulomatous pyelonephritis is a variant of chronic pyelonephritis that characteristically presents in middle aged patients with a poorly functioning kidney as in diabetic On histology there are areas of clear cells that are lipid-laiden macrophages These areas of lipid-laiden macrophage appear as fat density lesion on US This pyelonephritis is often accompanied by a calculus and proteus infection. Kidney sparing surgery is indicated for XGP. 