title: An ultrastructural study of mixed hepatoblastoma with osteoid elements.
abstract: A case of mixed hepatoblastoma with osteoid elements was studied by light and electron microscopy. The ultrastructure of the epithelial elements showed a lack of differentiation and simple cytoplasmic organelles. However, an occasional cytoplasmic crystalloid structure were seen. The ultrastructure of the osteoid foci showed fibroblast-like cells capable of collagen formation, clearly distinguishable from the epithelial elements. These cells had neoplastic characteristics of nuclear pleomorphism and high nucleo-cytoplasmic ratio. These findings support the belief that hepatoblastoma arises from a multipotential blastema capable of both epithelial and mesenchymal differentiation, with the osteoid elements being an intrinsic neoplastic component of the tumor.
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D002467:Cell Nucleus / Q000648:ultrastructure; D003094:Collagen / Q000032:analysis; D003593:Cytoplasm / Q000648:ultrastructure; D004847:Epithelial Cells; D004848:Epithelium / Q000648:ultrastructure; D005347:Fibroblasts / Q000648:ultrastructure; D006801:Humans; D002479:Inclusion Bodies / Q000648:ultrastructure; D007223:Infant; D008113:Liver Neoplasms / Q000473:pathology*; D008297:Male
chemical_list: D003094:Collagen