Clinicopathological features and post-resection outcomes of hepatocellular adenoma.

Backgrounds/Aims Hepatocellular adenomas (HCA) are rare benign liver tumors with the potential of malignant transformation and risk of bleeding. We investigated the clinicopathological features and outcomes of HCA in 19 patients who underwent surgical resection. Methods This retrospective observational study included 19 patients who underwent hepatic resection during a 9-year period from 2011 to 2019. Results The incidence of HCA was 0.18% of all hepatic resection cases during the study period. The mean age of the patients was 34.3±9.6 years, and 12 patients (63.2%) were female. Abdominal pain was present as initial clinical manifestation in 5 patients and the other 14 patients had no specific symptoms. HCA was diagnosed in 7 out of 8 patients who underwent liver biopsy. R0 resection was performed in 18 patients (94.7%) and laparoscopic liver resection was performed in 11 patients (57.9%). The mean tumor size was 5.6±3.6 cm and 17 patients had a single tumor. Immunohistochemical analysis of the resected tumor specimens revealed hepatocyte-nuclear-factor-1α mutated HCA in 2 (10.5%), β-catenin-mutated HCA in 2 (10.5%), inflammatory HCA in 12 (63.2%) and unclassified HCA in 3 (15.8%). There were no pathognomonic findings in the preoperative liver imaging studies among these four groups. Currently, all patients are alive with a mean follow-up period of 40.1±26.3 months. One patient showed residual tumors after incomplete resection. Conclusions Surgical resection may be indicated if imaging studies show diagnostic ambiguity, growing tumor or symptomatic mass. Because of the risk of tumor recurrence and malignant transformation, long-term follow-up is necessary.