[Histogenesis and classification of primary liver tumors in children]

Combined morphological examinations of 55 primary tumors of the liver in children as well as livers of 7 human embryos and fetuses were carried out. The finding in hepatoblastoma tissue of the elements of hepatic diverticulum of endoderm persisting in the tumor tissue and comparison of the study results with the data on the embryogenesis and organogenesis of human liver suggest that primary hepatic tumors originate from the pluripotent endodermal germination layer. Islets of tissues not found in the normal liver as well as "osteoid" and squamous epithelium most likely result from cataplasia of "polygonal" myoepithelial-like cells of biliary epithelium in the period of synthesis of basal membrane substance. A classification of primary liver tumors in children taking into account the level of tumor anlage in the ontogenesis and based on the histogenetic principle is proposed.