Structure of a hepatoblastoma of pure epithelial type

The epithelial cells of a hepatoblastoma of a 21-month-old child were studied by light and electron microscopy. This tumor was associated with the presence of α1-fetoprotein in the serum. Despite their presumed immaturity, the tumor cells were shown to possess an organelle complement compatible with a wide range of synthetic capacities. The arrangement of subcellular structures suggested that synthetic metabolic processes are particularly active in hepatoblastoma cells. It is speculated that metabolic products of such cells, of which α1-fetoprotein is the currently prominent example, might become of greater diagnostic value than in hepatocarcinoma of older age groups. Well-differentiated cells are structurally closer to morphologically altered hepatocytes than to tumor cells. More primitive cells have a simpler structure, but increasing complexity of ultrastructural organization suggests that transitional forms exist between the main cellular types. Greater uniformity of nomenclature is desirable concerning epithelial cells of hepatoblastoma.