title: Hepatocellular adenomas: accuracy of magnetic resonance imaging and liver biopsy in subtype classification.
abstract: Hepatocellular adenomas (HCAs) are divided into genotype/phenotype subgroups associated with different evolutive profiles. Therefore, recognition of subtype is of clinical importance in patient management. Magnetic resonance imaging (MRI) is considered the most informative imaging modality and liver biopsy a key diagnostic tool whose role in HCA subtyping has never been extensively studied. The purpose of our study was to evaluate the diagnostic performance of MRI and liver biopsy with and without immunohistochemistry and to assess the interobserver agreement for MR classification in a consecutive series of resected HCAs. Forty-seven HCAs with preoperative MRI and biopsy were retrospectively included. MRI data were reviewed independently by two abdominal radiologists blind to the pathological results and classification. Subtyping of HCAs on liver biopsy was made blindly to clinical, biological, and imaging data and to final classification. Routine histological analysis was based on morphological criteria and immunohistochemistry was systematically performed when enough tissue was available. Final subtyping of HCA was based on the examination of the surgical specimen. Radiologists correctly classified HCAs in 85%. The interobserver kappa correlation coefficient was 0.86. Routine histological analysis led to 76.6% of correct classification and 81.6% when immunophenotypical characteristics were available. The additional value of immunophenotypical markers is best in HCAs containing steatosis. Agreement between MRI findings and routine histological analysis was observed in 74.5%, leading to a likelihood ratio of subtype diagnosis higher than 20.
  
  
  CONCLUSIONS
  MRI and biopsy analysis are two efficient methods in subtyping HCAs and their association increases the diagnosis confidence. Interobserver variability in MRI criteria is very low.
authors.affiliation: Department of Radiology, Hôpital Beaujon Clichy, France; INSERM U773, centre de recherche biomédicale Bichat-Beaujon, Paris, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Ronot
authors.forename: Stephane
authors.initials: S
authors.lastname: Bahrami
authors.forename: Julien
authors.initials: J
authors.lastname: Calderaro
authors.forename: Dominique-Charles
authors.initials: DC
authors.lastname: Valla
authors.forename: Pierre
authors.initials: P
authors.lastname: Bedossa
authors.forename: Jacques
authors.initials: J
authors.lastname: Belghiti
authors.forename: Jacques
authors.initials: J
authors.lastname: Belghti
authors.forename: Valérie
authors.initials: V
authors.lastname: Vilgrain
authors.forename: Valérie
authors.initials: V
authors.lastname: Paradis
mesh_terms: D018248:Adenoma, Liver Cell / Q000145:classification* / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000145:classification* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies