title: [Management of cystic renal masses: Review of the literature].
abstract: BACKGROUND
  The expansion of renal cysts diagnosis in the population entails to learn how to properly identify and treat potentially malignant lesions. The aim of this review article is to discuss anatomical and pathological characteristics as well as treatment of cystic renal tumors.
  
  
  METHODS
  A literature review of Medline publications on renal cysts and cystic tumors was conducted. Prospective and retrospective studies in adults, and previous reviews were analyzed.
  
  
  RESULTS
  Bosniak classification of renal cysts is used worldwide among urologists and radiologists to categorize cystic lesions according to their potential malignancy. There is a 0, 15, 50 and 95 % chance of cancerous cells in Bosniak I, II, III, and IV, respectively. The most frequent pathology is renal cell carcinoma, usually low grade and low stage. Category IIF cysts (F for follow-up) have a 25 % chance of malignancy and require surveillance at 6 months and regularly for 5 years. The follow-up can be done with CT imaging, MRI or contrast enhanced ultrasonography. Cyst biopsy, which was not recommended for a long time, could prevent 40 % of unnecessary surgeries for benign lesions. Bosniak category I and II cysts can be treated if symptomatic, by sclerotherapy or laparoscopic deroofing of the cyst. Category III and IV lesions must be treated as malignant tumors with security margins.
  
  
  CONCLUSIONS
  Diagnosis and treatment of Bosniak category IIF renal cysts remain the primary challenge for physicians in cystic renal tumor management. Biopsies of renal cysts seem reliable, with no risk of malignant cell dissemination.
authors.affiliation: Service d'urologie et transplantation rénale, CHU de Grenoble, 38043 Grenoble cedex 9, France; Laboratoire TIMC-IMAG, domaine de la Merci, 38700 La Tronche, France.
authors.forename: C
authors.initials: C
authors.lastname: Lanchon
authors.affiliation: Service d'urologie et transplantation rénale, CHU de Grenoble, 38043 Grenoble cedex 9, France; Laboratoire TIMC-IMAG, domaine de la Merci, 38700 La Tronche, France.
authors.forename: G
authors.initials: G
authors.lastname: Fiard
authors.affiliation: Service d'urologie et transplantation rénale, CHU de Grenoble, 38043 Grenoble cedex 9, France; Laboratoire TIMC-IMAG, domaine de la Merci, 38700 La Tronche, France. Electronic address: JALong@chu-grenoble.fr.
authors.forename: J-A
authors.initials: JA
authors.lastname: Long
mesh_terms: D000328:Adult; D001706:Biopsy; D003952:Diagnostic Imaging; D006801:Humans; D007668:Kidney / Q000473:pathology / Q000601:surgery; D052177:Kidney Diseases, Cystic / Q000145:classification* / Q000601:surgery*; D011230:Precancerous Conditions / Q000175:diagnosis
keywords: Bosniak classification; CCR; Carcinome à cellules rénales kystique; Classification de Bosniak; Complex renal mass; Cystic renal cell carcinoma; Cystic renal tumor; Kyste complexe du rein; Kyste rénal; RCC; Renal cyst; Tumeur kystique