title: Xanthogranulomatous pyelonephritis presenting with a left flank mass.
abstract: We present a case of a patient with xanthogranulomatous pyelonephritis (XGP) presenting with a large (18 × 12 cm) left-sided flank mass with worsening left flank pain. CT abdomen/pelvis demonstrated a left kidney with parenchyma replaced by multiple large hypodense collections containing fluid and gas, a left staghorn calculus, and a communication between the kidney and large flank collection. About 4.5 weeks after initial presentation, the patient underwent operative intervention. Pathology revealed an end-stage kidney with scar consistent with xanthogranulomatous pyelonephritis.
authors.affiliation: Department of Urology, University of California San Francisco, 400 Parnassus Avenue, San Francisco, CA 94143, USA.
authors.forename: Uwais B
authors.initials: UB
authors.lastname: Zaid
authors.affiliation: Department of Urology, University of California San Francisco, 400 Parnassus Avenue, San Francisco, CA 94143, USA.
authors.forename: Sima P
authors.initials: SP
authors.lastname: Porten
authors.affiliation: Department of Urology, University of California San Francisco, 400 Parnassus Avenue, San Francisco, CA 94143, USA.
authors.forename: Nadya M
authors.initials: NM
authors.lastname: Cinman
authors.affiliation: Department of Urology, University of California San Francisco, 400 Parnassus Avenue, San Francisco, CA 94143, USA.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Sanford
authors.affiliation: Department of Urology, University of California San Francisco, 400 Parnassus Avenue, San Francisco, CA 94143, USA.
authors.forename: Benjamin N
authors.initials: BN
authors.lastname: Breyer