Hepatocellular adenoma in Taiwan: Distinct ensemble of male predominance, overweight/obesity, and inflammatory subtype

Background and Aim The clinicopathologic features of hepatocellular adenoma in Asian populations have been poorly defined. The study aimed to characterize this rare entity in a single institution in Taiwan. Methods In total, 45 hepatocellular adenomas from 1995 to 2018 were included and sent for pathologic review and molecular subtyping. Results The numbers of patients with hepatocellular adenoma has doubled in the recent decade. Surprisingly, men outnumbered women in our cohort (n = 26, 58% vs N = 19, 42%). A collection of clinical information revealed that overweight/obesity accounts for most of the associated conditions of hepatocellular adenoma. Only three women took oral contraceptives. There were 34 inflammatory (75%), three LFABP‐negative (7%), four β‐catenin activated (9%), and four unclassified (9%) hepatocellular adenomas. Ten inflammatory hepatocellular adenomas demonstrated strong and homogeneous glutamine synthetase staining and were thus also β‐catenin activated. Notably, overweight and obesity were significantly associated with inflammatory hepatocellular adenoma than other subtypes (P = .029 and .056, respectively) and were strongly correlated with steatosis in background liver (P = .028 and.007, respectively). Malignant transformation (four borderline tumors and two hepatocellular carcinomas) was identified in six adenomas (two women and four men). All six hepatocellular adenomas with malignancy were β‐catenin activated; β‐catenin activation could serve as a biomarker for malignant progression. Conclusions The clinicopathologic features of hepatocellular adenoma in Taiwan are distinct from those reported in Western countries. Rare oral contraceptive usage and an emerging epidemic of overweight/obesity in Taiwan provides new insights into the pathogenesis of hepatocellular adenoma.