Depressed-Type Colonic Lesions and “De Novo” Cancer in Familial Adenomatous Polyposis: A Colonoscopist’s Viewpoint

Figure 1

“Adenoma-carcinoma sequence” and “de novo” theory regarding the development/progression of colorectal neoplasms. In the adenoma-carcinoma sequence, lesions grow and protrude and finally develop to ulceration; this is called the “mountain route.” Depressed-type lesions develop by the de novo pathway. This is called the “direct route.”