Etiology and Pathogenesis
Nothing is known directly about the cause of colonic polyps other than the role of inheritance in the familial polyposis syndromes to be noted later. There is considerable evidence, albeit most of it indirect, that most if not all carcinomas of the colon derive from previously benign polyps, most commonly after at least 10 to 15 years. If this is so, one would expect that the risk factors that have been defined for colonic carcinoma might also prove to pertain to benign polyps as well. Clearly only a very small percentage of benign polyps progress to malignancy, although the definite existence of this potential usually makes it advisable to remove any demonstrated colonic adenomatous polyp.