Ultrastructure of hepatocellular carcinoma in a cirrhotic liver.

Hepatoma cells, though sharing many similarities with non-neoplastic hepatocytes, showed conspicuous alterations--increased nuclear/cytoplasmic ratio, intranuclear invapinations of cytoplasm, lipoid material, high mitotic activity, and the presence of abundant small fat droplets and glycogen in the cytoplasm. "Capillarization" of sinusoids was a constant feature with the appearance of junctions between endothelial cells, deposition of fibrillary material in Disse's spaces, flattening of hepatocyte microvilli and deposition of basement-membrane-like material. Abundant microtubules and the presence of annulate lamellae were other features noted in the tumor cells.