Unclassified Hepatocellular Adenoma Research Articles

Overview of hepatocellular adenoma in Japan.

Hepatocellular adenoma (HCA) is generally a benign hepatocellular tumor arising in a nonfibrotic/cirrhotic liver, and recently four major subgroups were identified based on genotype and phenotype classification from Europe. HCA is rare in Asian countries including Japan, and there have been few studies regarding the subgroups of HCA in Japan. We surveyed subgroups of HCA in 13 patients (7 women) in Japan, based on the phenotypic classification. As results, we identified 2 hepatocyte nuclear factor (HNF) 1α-inactivated HCAs (15%), two β-catenin-activated HCAs (15%), 5 inflammatory HCAs (39%), and 4 unclassified HCAs (29%). The use of oral contraceptives was found only in 2 unclassified HCAs (29%). Rather low percentage of female patients and use of oral contraceptives appear to be common clinicopathological features in Japan and also East Asian countries. Furthermore, a group of possible inflammatory HCAs characterized by strong immunoreactivity for serum amyloid A (SAA) was found in patients with alcoholic cirrhosis. The inflammatory HCA/SAA-positive hepatocellular neoplasm in alcoholic cirrhosis may be a new entity of HCA, which may have potential of malignant transformation. Further studies are needed to clarify genetic changes, monoclonality, and pathogenesis of this new type of hepatocellular neoplasm.

Characterization of hepatocellular adenoma based on the phenotypic classification: The Kanazawa experience

Hepatocellular adenoma (HCA) represents a heterogeneous entity, and recently four major subgroups were identified based on genotype and phenotype classification from Europe. HCA is rare in Asian countries including Japan and there has been no study regarding the subgroups of HCA in Japan. We took advantage of the reported genotype/phenotype classification to analyze 14 HCA (seven women) in Japan. We identified one hepatocyte nuclear factor (HNF)1α-inactivated HCA (one woman), two β-catenin-activated HCA (one woman), seven inflammatory HCA (IHCA, two women); four additional cases (three women) had no known phenotypic marker (unclassified HCA). The use of oral contraceptives was found only in two unclassified HCA (29%) cases. Fatty change of the background liver was seen in one β-catenin-activated HCA cases, four IHCA (57%) and two unclassified HCA (50%). Hepatic fibrosis was seen in five IHCA (71%) and two unclassified HCA (50%) cases. Four IHCA patients (one woman) were alcohol drinkers and one had alcoholic steatofibrosis and three had alcoholic cirrhosis. Eight HCA (57%) were multiple; one HNF1α-inactivated HCA (100%), four IHCA (57%) and three unclassified HCA (75%). The tumor was significantly larger in β-catenin-activated HCA than in other subgroups. The association of hepatocellular carcinoma was seen only in one case of unclassified HCA. This study suggests that IHCA arising in men with alcoholic liver disease may be a major subtype of HCA in Japan.