Sinusoids ultrastructure of human hepatocellular carcinoma.

Sinusoids ultrastructure was studied in a case of hepatocellular carcinoma developed in the non cirrhotic liver of a 40-year-old man. The surgical biopsy was perfusion-fixed with 1.5% glutaraldehyde. The number of Kupffer cells was very low. Endothelial cells with signs of hyperactivity were very irregular; digitations were often attached by numerous well identified junctional complexes to their own cell processes or to adjacent cell processes. Perisinusoidal cells without lipids resembled fibro-myofibroblasts. Discontinuous basement membranes underlaid endothelial cells and perisinusoidal cells. In addition numerous strands of short basement membranes segments were seen in the Disse space. Well organized bundles of collagen were not seen. The sinusoidal membranes of hepatocytes were flattened. The perfusion-fixation revealed to be a very useful technique in the identification of all these changes which have also been reported to some degree in benign liver cell adenoma and in cirrhosis; these two conditions are known to be associated with hepatocellular carcinoma.