title: [Congenital hepatoblastoma of mixed type. Light and electron microscopy studies].
abstract: Malignant liver tumors of infancy are uncommon. In this report the histological and ultrastructural features of a congenital mixed hepatoblastoma in a female infant are described. The tumor was obtained by radical surgery at the eighth day of life. Histologically the mass was characterized by a mixture of variously differentiated hepatic tissue and mesenchymal tissue. The epithelial component is represented by liver cells of the embryonic and fetal type. Electron microscopical investigation revealed a changing organelle composition of the epithelial tumor cells showing a decreased number of cytoplasmic organelles in the cells of the embryonic type. At cellular junctions, however, these cells are connected by desmosome-like structures without lumina as well as empty canaliculi-developing structures of cholangiolar microvilli. At light microscopical level the former corresponded to pseudorosettes , the latter to so-called rosettes. Furthermore, in places sinus-like structures are encountered but in the absence of true sinusoidal channels with Disse's spaces. Some areas consisted of undifferentiated cells lacking cytoplasmic organelles and resembled a multipotential blastema. The ultrastructural findings suggest that hepatoblastoma may arise from an undifferentiated progenitor cell capable of various forms of differentiation.
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000151:congenital* / Q000648:ultrastructure; D003896:Desmosomes / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008113:Liver Neoplasms / Q000151:congenital* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008871:Microvilli / Q000648:ultrastructure
vernacular_title: Konnatales Hepatoblastom vom Mischtyp. Licht- und elektronenmikroskopische Untersuchungen.