title: Chronic pyelonephritis presenting as a renal sinus tumor with retroperitoneal extension: a case report.
abstract: BACKGROUND
  Chronic pyelonephritis is associated with progressive renal scarring and occurs, most of the time, in patients with major anatomical anomalies, including urinary tract obstruction, calculi, renal dysplasia or vesicoureteric reflux. We report the computed tomography imaging findings of a patient with chronic pyelonephritis appearing as a renal sinus mass. To our knowledge, it is the first time that such a case has been published in the literature.
  
  
  METHODS
  We present a case of a 68-year-old woman who underwent a computed tomography scan of the abdomen in the work-up for recently diagnosed hypertension. A non-enhancing left renal sinus mass was detected extending to the para-aortic space. The initial diagnosis was that of a tumor of the collecting system. Nephro-ureterectomy was performed and the pathology results revealed changes of chronic pyelonephritis.
  
  
  CONCLUSIONS
  Chronic pyelonephritis presenting as a renal sinus mass is reported for the first time in the literature. This may lead to the conclusion that diagnostic ureteropyeloscopy and biopsy should be performed prior to radical surgery for possible upper tract urothelial tumors.
authors.forename: Georgios I
authors.initials: GI
authors.lastname: Papadopoulos
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Mountanos
authors.forename: Stylianos I
authors.initials: SI
authors.lastname: Manolakakis
authors.forename: Georgios
authors.initials: G
authors.lastname: Chrysanthakopoulos
authors.forename: Eugenia
authors.initials: E
authors.lastname: Papaliodi
authors.forename: Antonios D
authors.initials: AD
authors.lastname: Farmakis