Diffuse Xanthogranulomatous pyelonephritis: A Rare Disease With A Common Presentation.

Xanthogranulomatous pyelonephritis (XGP) is a distinct entity characterized by chronic granulomatous changes in the renal parenchyma associated with renal destruction and urinary tract abnormalities, most often from obstruction or infection in the urinary tract. We have presented the case report of a girl with fever, abdominal pain, vomiting, anorexia, and weight loss. Computed tomography of the abdomen showed multiloculated cystic lesions with calcifications and a psoas muscle abscess, which tested positive for Escherichia (E.) coli. Histopathology revealed lipid-laden macrophages, multinucleated giant cells, and fibrosis. Nephrectomy and drainage of the psoas abscess were done. XGP, although rare, should not be confused with renal tumors and should be considered in children presenting with fever and urinary tract symptoms. Early diagnosis can be reached with CT. Nephrectomy is the definitive treatment.