A scanning electron microscopic study on the peritoneal implantation of ascites hepatoma AH100B cells in rats

The process and mechanism of peritoneal metastasis of tumor cells were studied experimentally by means of scanning or transmission electron microscopy, employing rat ascites hepatoma AH100B. Adhesion of tumor cells by microvilli and/or pseudopodia to the mesothelium was observed within 1 approximately 3 days after inoculation when there was no morphological changes of the mesothelial cells. Some changes of the mesothelial cells, such as irregularity, atrophy, and exfoliation, followed tumor cell adhesion 5 or 6 days after inoculation. It was noted that tumor cells adhered to the mesothelium first where no morphological changes were induced, and it is suggested that tumor cells infiltrate into the submesothelial tissue through mesothelial defects.