title: Malignant transformation of hepatocellular adenomas into hepatocellular carcinomas: a systematic review including more than 1600 adenoma cases.
abstract: BACKGROUND
  Malignant transformation of hepatocellular adenomas (HCAs) into hepatocellular carcinomas (HCCs) has been reported repeatedly and is considered to be one of the main reasons for surgical treatment. However, its actual risk is currently unknown.
  
  
  OBJECTIVE
  To provide an estimation of the frequency of malignant transformation of HCAs and to discuss its clinical implications.
  
  
  METHODS
  A systematic literature search was conducted using the following databases: The Cochrane Hepatobiliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, MEDLINE and EMBASE.
  
  
  RESULTS
  One hundred and fifty-seven relevant series and 17 case reports (a total of 1635 HCAs) were retrieved, reporting an overall frequency of malignant transformation of 4.2%. Only three cases (4.4%) of malignant alteration were reported in a tumour smaller than 5 cm in diameter.
  
  
  CONCLUSIONS
  Malignant transformation of HCAs into HCCs remains a rare phenomenon with a reported frequency of 4.2%. A better selection of exactly those patients presenting with an HCA with an amplified risk of malignant degeneration is advocated in order to reduce the number of liver resections and thus reducing the operative risk for these predominantly young patients. The Bordeaux adenoma tumour markers are a promising method of identifying these high-risk adenomas.
authors.affiliation: Department of Surgery, Maastricht University Medical Centre, Maastricht, the Netherlands. jan@stoot.com
authors.forename: Jan H M B
authors.initials: JH
authors.lastname: Stoot
authors.forename: Robert J S
authors.initials: RJ
authors.lastname: Coelen
authors.forename: Mechteld C
authors.initials: MC
authors.lastname: De Jong
authors.forename: Cornelis H C
authors.initials: CH
authors.lastname: Dejong
mesh_terms: D000236:Adenoma / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000601:surgery; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor