Fast-growing cancer of the colon and rectum.

Recently, the existence of a flat, colorectal cancer has been proposed. This cancer is completely different in appearance from ordinary polyp cancer and is believed to invade deeply into the submucosa, even in its early stages. Its characteristics are quite different from cancers that follow the adenoma-cancer sequence, and it requires a greater search to detect. The authors observed four cases of fast-growing cancer that were relatively flat in appearance, contained no adenomatous component, and were invasive, even in their early stages.