Pictures of focal nodular hyperplasia and hepatocellular adenomas

Core Tip

Core tip: In this paper are illustrated macroscopic and microscopic aspects of focal nodular hyperplasia and hepatocellular adenoma. These illustrations represent typical as well as less usual aspects of these two benign hepatocellular tumors. Microscopic pictures are performed using classical routine stains such as HE, trichrome or cytokeratin 7 or less usual markers proven of great interest to identify focal nodular hyperplasia (FNH) such as glutamine synthase or liver fatty acid briding protein, C reactive protein or b catenin to identify hepatocyte nuclear factor 1 alpha mutated hepatocellular adenoma (HCA), inflammatory HCA, β-catenin mutated HCA respectively. These illustrations combined with brief clinical information should be helpful for pathologists for their practice. Indeed if FNH are rather frequent tumor easy to recognize, there are difficulties when key features are lacking or when features such as steatosis or sinusoidal dilatation, features of HCA, are present. The great message of this paper is the possibility to identify HCA subtypes, a key feature for the coming years to better manage patients.