title: Hepatocellular adenoma and focal nodular hyperplasia: a series of 24 patients with clinicopathological and radiological correlation.
abstract: OBJECTIVE
  To investigate two rare benign lesions, hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH), and evaluate differential diagnosis.
  
  
  METHODS
  Twenty-four consecutive patients with presumed HCA and FNH were studied at the Liver Cancer Institute from January 1996 to May 1999. Preoperative assessment included clinical evaluation, symptoms and laboratory tests. New imaging techniques were prospectively appraised in addition to usual techniques. All had hepatic resections and follow-up. Histologic examination of surgical specimens was obtained in all cases.
  
  
  RESULTS
  In every instance, FNH was an incidental finding. FNH consists of nodular aggregates of cytologically normal hepatocytes with foci of intranocular bile duct proliferation. In this series, patients with HCA had larger tumors and more often were symptomatic but the occurrence was unrelated to oral contraceptive steroids (OCS) usage. Intralesional hemorrhage or necrosis is common, and was seen in 75% of cases. The best imaging procedure in the diagnosis of FNH was MRI. Color Doppler US was a useful adjunct, but CT lacked specificity, making histological diagnosis mandatory. All patients underwent tumor resected were tumor--free during the follow-up.
  
  
  CONCLUSIONS
  FNH is a distinct histopathologic entity, and is distinguishable from HCA. FNH is a hyperplastic response by the liver parenchyma to a pre-existing arterial malformation. HCA is a liver neoplasia and has the potential of malignant transformation to HCC. Based on these findings, we believe that if the clinical suspicion of HCA or FNH is strong, resection is usually the best approach if technically feasible and histologic diagnosis is mandatory.
authors.affiliation: Department of Pathology, Zhongshan Hospital, Shanghai 200032, China. newera.ji@yahoo.com
authors.forename: Y
authors.initials: Y
authors.lastname: Ji
authors.forename: X
authors.initials: X
authors.lastname: Zhu
authors.forename: H
authors.initials: H
authors.lastname: Sun
authors.forename: Y
authors.initials: Y
authors.lastname: Tan
authors.forename: Z
authors.initials: Z
authors.lastname: Ma
authors.forename: Q
authors.initials: Q
authors.lastname: Ye
authors.forename: A
authors.initials: A
authors.lastname: Sujie
authors.forename: Z
authors.initials: Z
authors.lastname: Tang
mesh_terms: D018248:Adenoma, Liver Cell / Q000000981:diagnostic imaging / Q000473:pathology*; D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D020518:Focal Nodular Hyperplasia / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D011859:Radiography