Les tumeurs hépatocellulaires bénignes, données morphologiques et moléculaires: une nouvelle classification
Benign hepatocellular tumors, morphological and molecular data: a new classification
Benign hepatocellular tumors occur frequently in the same context of young women using oral contraception.
The most frequent type is Focal Nodular Hyperplasia (FNH), often easy to diagnose in its classical form. FNH are polyclonal lesions, considered as a regenerative process and not as a true tumor. They expressed a high Ang1/Ang2 ratio, supporting the concept of a vascular trigger in the pathogenesis of FNH.
Adenomas represent the other group of benign hepatocellular tumors, much rarer than FNH. They can be solitary, multiple or in the context of an adenomatosis (more than 10 nodules). Adenoma / adenomatosis are constantly monoclonal tumors. They are considered now as a heterogeneous entity. According to genotype-phenotype correlations, 4 groups of adenomas have been identified and a new classification has been proposed.
- HNF1α-mutated adenomas are characterized by marked steatosis and represent the most important group (nearly 50%).
- β-catenin mutated adenomas (about 15%) have a higher risk of malignant transformation.
- The third group of adenomas accounting for approximately 20% of adenomas, exhibit inflammatory infiltrates, often associated with numerous and dystrophic vessels, sometimes a more or less obvious ductular reaction; therefore, they resemble, at least partly, to the entity previously called “telangiectatic FNH”; they have to be managed as adenomas, since they can bleed. This entity could be better named “inflammatory and/or telangiectatic adenoma”.
- The fourth group has no particular morphological and molecular features.
In addition to morphological studies and molecular tools, specific and sensitive immunohistochemical markers remain to be found to efficiently classify all these benign hepatocellular tumors.
focal nodular hyperplasia, hepatocellular adenomas, HNF1α mutations, β-catenin mutations, inflammatory / telangiectatic adenomas