Abstract

The etiologic impacts in primary hepatocellular carcinoma among Koreans seem different from those in other countries with its high incidence and close association of hepatitis B virus infection and liver cirrhosis. A series of 35 lobectomy specimens of hepatocellular carcinoma (HCC) was examined by means of electron microscopy to elucidate the general ultrastructural characteristics and to understand the morphogenesis of various histological growth patterns and cytologic features of HCC. 1) General cytological details of HCC were similar to those of non-neoplastic hepatocytes, but characterized by scantiness of subcellular organelles. Degree of cellular differentiation was not correlated with ultrastructural features of HCC. 2) Acinar pattern of HCC seemed to develop by either dilatation of central bile canaliculus or central cystic degeneration of microtrabecular growth, and clear cell group of HCC was expressed in abundance of glycogen particles and lipid droplets. 3) Intranuclear inclusions of HCC proved to be cytoplasmic herniations of tumor cells, and intracytoplasmic tubular arrays appeared to originate from the endoplasmic reticulum. 4) Hyaline globules seen in HCC corresponded to clumps of microfilamentous structures similar or identical to Mallory's hyalin.