title: Evaluation of Bosniak category IIF complex renal cysts.
abstract: OBJECTIVE
  To evaluate moderately complex renal cysts of Bosniak category IIF.
  
  
  METHODS
  The regional ethics committee approved the study. In the period 2003-2009, radiological CT reports of 8,402 CT examinations of the kidneys were analysed retrospectively by one radiologist. All complex cystic lesions in the kidney (n = 550 in the same number of patients) were reclassified according to the Bosniak classification by two radiologists in consensus. If a patient had more than one lesion, only the highest Bosniak category was recorded. All Bosniak IIF lesions with ≥2-year follow-up were included in the study.
  
  
  RESULTS
  Thirty-two Bosniak IIF lesions were found. Five lesions (16 %) were upgraded during follow-up and the patients were offered surgery. Pathology of three lesions showed papillary carcinoma, clear cell renal carcinoma and chronic inflammation, respectively. Due to comorbidity the remaining two patients were followed with CT without intervention. Ten lesions (31 %) with follow-up periods >5 years had no further radiological changes and clinical follow-up was stopped.
  
  
  CONCLUSIONS
  The use of Bosniak category IIF is clinically applicable, resulting in an overall surgical nephron-sparing approach to complex renal cysts.
  
  
  CONCLUSIONS
  • The Bosniak classification is used to categorise complex renal cystic masses • BIIF cysts behave mostly as benign lesions • Radiological progression in complexity occurs in only 16 % of cases • BIIF category seems promising for clinical application, potentially avoiding unnecessary surgery.
authors.affiliation: Urological Research Center, Department of Urology, Fredericia Hospital, Fredericia, and Institute of Regional Health Services Research, University of Southern Denmark, Dronningensgade 97, DK-7000, Fredericia, Denmark, olegraumann@dadlnet.dk.
authors.forename: Ole
authors.initials: O
authors.lastname: Graumann
authors.forename: Susanne Sloth
authors.initials: SS
authors.lastname: Osther
authors.forename: Jens
authors.initials: J
authors.lastname: Karstoft
authors.forename: Arne
authors.initials: A
authors.lastname: Hørlyck
authors.forename: Palle Jörn Sloth
authors.initials: PJ
authors.lastname: Osther