A Shifting Paradigm in Diagnosis and Management of Hepatic Adenoma.

backgroundNew insights into molecular pathogenesis of hepatocellular adenomas (HCA) have allowed sub-classification based on distinct genetic alterations and a fresh look at characterizations of natural history. Clinically, this is important in understanding risk factors for two feared complications: malignant transformation and hemorrhage.

methodsPubMed literature search for hepatocellular adenoma over all years, excluding case reports and articles focusing on multiple adenomas or adenomatosis.

resultsThe β-catenin exon 3 mutated HCA accounts for about 10% of all HCAs and is associated with the highest risk of malignant transformation. The HF1α subtype accounts for 30-40% of all HCAs and has the lowest risk of malignant transformation. Gender has also emerged as an increasingly important risk factor and males with HCA are at considerably higher risk of malignant transformation, regardless of tumor size. The increasing use of gadoxetic-enhanced MRI has allowed for improved differentiation of HCAs from focal nodular hyperplasia, as well as the identification of specific radiologic features of some subtypes, particularly the inflammatory and HF1α HCAs.

conclusionsClassification of HCA by subtype has important implications for patient counseling and treatment given variable risks of malignant transformation and hemorrhage. Males and those with β-catenin exon 3 mutated HCAs are two groups who should always be counselled to undergo surgical resection. On the other hand, in the lower risk HF1α subtype observation is appropriate in lesions < 5 cm and may even be considered in larger lesions as longer follow-up data is aggregated and tumorigenesis is better understood.