Borderline hepatocellular adenomas (BL-HCA) are characterized by focal architectural/cytologic atypia and reticulin loss, features that are insufficient for a definitive diagnosis of hepatocellular carcinoma (HCC). The diagnosis and management of BL-HCA are challenging as their biological behavior, especially in terms of malignant potential, is still debated.

Our guest, Dr. Nicolas Poté, from the Université Paris Cité in Paris, France, discusses his team's recent study comparing the clinicopathologic and molecular features of BL-HCA with those of typical HCA (T-HCA), HCA with malignant transformation (HCC on HCA), and HCC to assess the risk of malignancy. Somatic mutations, including TERT promoter mutations associated with HCA malignant transformation and gene expression levels of 96 genes, were investigated.

In comparison with T-HCA, BL-HCA were significantly enriched for exon 3 mutations of β catenin gene (41% vs 6%; P < .001). By gene expression profiling BL-HCA overlapped with T-HCA and HCC on HCA, favoring a molecular continuum of the tumors. TERT promoter mutations were observed only in HCC on HCA (42%) and in HCC (38%). The authors propose a decision algorithm for the management of BL-HCA based on their morphologic and molecular features in biopsy samples.