[Electron microscopic observation of primary cultured laterally spreading tumor cell line].
To observe the microscopic characteristics of laterally spreading tumor (LST) cell line in primary culture. The cells isolated from a rectum LST specimen obtained by endoscopic mucosal resection was primary cultured, followed by observation with scanning and transmission electron microscope in comparison with the cells of adenocarcinoma and normal mucosa of the rectum. Scanning and transmission electron microscopes both revealed numerous microvilli covering the surface of the LST cells, and the cytoplasm contained large quantity of lysosomes, mitochondria and phagosomes. Obviously heterogeneous cell nuclei were present with abnormal nuclear fossa and huge nucleoli. The cultured LST cells are highly malignant.