Systematic review of haemorrhage and rupture of hepatocellular adenomas (Br J Surg 2012; 99: 911-916)

Molecular classification of hepatocellular adenoma: A single-center experience

BACKGROUNDS/AIMS

Hepatocellular adenoma (HCA) is a rare benign tumor that has a risk of malignant transformation into hepatocellular carcinoma (HCC) and bleeding. The aim of this study was to analyze the characteristics of HCA by performing molecular classification.

METHODS

We retrospectively collected data from nine patients who were diagnosed with HCA from 1995 to 2016. The patients underwent liver surgery due to the existence of clinical symptoms. Immunohistochemical (IHC) staining was performed to classify the subgroups of HCA.

RESULTS

Four patients with both β-catenin and inflammation were classified as β-IHCA. Two patients were defined as β-HCA. Two patients were classified as HHCA. Only one patient was defined as IHCA. None of the patients had unclassified HCA. Seven of nine patients had a malignant transformation. By comparing the characteristics of HCA between two groups, we found the mean tumor size in the malignant transformation group was greater than the non-malignant transformation group.

CONCLUSIONS

Taken together, the mean tumor size and activation of catenin β1 mutation status might be the risk factors for the malignant transformation of HCA into HCC. Moreover, IHCA without the catenin β1 mutation could also have a possibility of malignant transformation into HCC.

Hepatocyte Nuclear Factor 1α-Mutated Hepatocellular Adenomas: An Atypical Presentation

Hepatocellular adenomas (HCAs) are rare benign monoclonal hepatic tumors that commonly occur in females (3-4 per 100,000 women) due to the use of oral contraceptives, its primary risk factor. Recently, HCAs have been classified into 4 distinct subtypes according to genotypic and phenotypic characteristics and clinical features: inflammatory HCA (40-50%), which are hypervascular with marked peliosis and a tendency to bleed; hepatocyte nuclear factor 1α (HNF1A)-mutated HCA (H-HCA, 30-40%) that are diffusely steatotic and rarely undergo malignant transformation; β-catenin activated HCA (10-15%), which frequently undergo malignant transformation and may seem hepatocellular carcinoma on imaging; and unclassified HCA (10-25%). In this study, we report the case of a 23-year-old female oral contraceptive user with H-HCA. Usually, H-HCA is considered to be nonsevere in most cases and often requires outpatient follow-up. However, in this case, the injury had substantially increased in volume and evolved with a major bleeding frame, which was an unusual finding for this subtype of adenoma. The therapeutic used for this patient was a laparoscopic left hepatic segmentectomy. Thus, the choice of treatment to be performed in a patient with H-HCA can depend on the tumor size (>5 cm), the outcome of previous bleeding, and the risk of bleeding recurrence.