Abstract

Primary malignant epithelial neoplasms of the liver, namely hepatoblastoma and hepatocarcinoma in infants and children are relatively rare in comparison with those arising in the kidney, adrenal gland, eye, central nervous systems and lymphopoietic system, comprising no more than 0.2 to 5.8 per cent of the total number of malignant tumors, excluding leukemia, in these age groups. In the past, most cases in the literature were form Caucasians, and the strange absence of reports of carcinomas of the liver in infancy and childhood from those parts of the world where adult hepatic neoplasm is prevalent was previously pointed out. This skepticism, however, has been recently effaced by cumulative reports of cases in Asia and the largest series of histopathologic study in the world literature contained 70cases collected in Japan. Since the first document on these neoplasms from our institute, reports of 19 cases have been accumulated in Korean literature until 1978. These comprise around 3 per cent of all malignant tumors excluding leukemia, of pediatric age group in Korea, which is comparable with the figure of 3.9 per cent in Japan. Because of the variety and multiplicity of the histologic composition of hepatoblastomas, they have been reported under various terms, such as embryonal hepatoma, mixed tumor, malignant adenoma, teratoma and teratoid hepatic carcinoma. In recent years, the importance of differential diagnosis of hepatoblastoma form hepatocarcinoma in infancy and childhood has been emphasized, because of comparatively benign character of the former, following radical surgery. It was Wilis, who first contended that the embryonal hepatic neoplasm, hepatoblastoma, of infancy and childhood should be separated from the adult type hepatoma which also occurs in this age group, and later Ishak and Glunz modified his classification with wide acceptance; malignant epithelial neoplasms of infancy and childhood are divided into two categories, hepatoblastoma and hepatocellular carcinoma and the former contains two types, an "epithelial" and "mixed epithelial and mesenchymal" type. However, very limited information is available about the ultrastructure of heptoblastoma and hepatocellular carcinomas of infants and children and two different views have been advanced in the literature. The objectives of this paper are to outline the histopathologic observation of 14 cases of heptic carcinoma in infancy and childhood in Korea and to contribute towards further understanding of their ultrastructural organization.