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.