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.