Genotype–phenotype classifications have led to the identification of five distinct subtypes based on morphological and immunophenotypical features, which are currently used in clinical practice: hepatocyte nuclear factor (HNF)-1α-inactivated HCA (H-HCA), inflammatory HCA (I-HCA), β-catenin-exon-7/8-mutated HCA (bex7/8-HCA), β-catenin-exon-3-mutated HCA (bex3-HCA), sonic hedgehog HCA (shHCA), and unclassified HCA, with two mixed forms derived from I-HCA and the two variants of b-HCA [2–4]. This evidence concerns the gene HNF1A and hepatocellular adenoma.