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Intestinal Polyp Definition
Intestinal Polyp is a fleshy growth, also called an intestinal polypoid ADENOMA, that grows from the mucous membrane lining of the COLON or RECTUM.There are two common types of intestinal polyps, neoplastic adenomas and hyperplastic adenomas, both of which grow almost exclusively in the colon. Neoplastic adenomas are neoplastic (abnormal growths that have no purpose or function in the body) and have the potential to turn malignant. Hyperplastic adenomas are not neoplastic and have no malignant potential.
Intestinal Polyp As a Cancer Risk Factor
Adenomas of either type arise from the epithelial cells, which make up the surfaces of membranes as well as the SKIN. Epithelial cells continuously renew themselves to replace worn and damaged epithelial tissues. Protein messengers tell healthy cells when to stop growing, containing the structures they form. When this regulatory mechanism goes awry cells continue to grow, forming abnormal structures such as adenomas. Adenomas, in the intestinal tract as well as elsewhere in the body, become more common with increasing age.
Various circumstances converge that permit ADENOMA-TO-ADENOCARCINOMA transition. Though only a small percentage of intestinal polyps become cancerous, more than 95 percent of COLORECTAL CANCER evolves from intestinal polyps. Typically this transition takes 5 to 10 years or longer, during which biopsy can detect the changes in the cells (DYSPLASIA). Cancer experts recommend removal of all intestinal polyps to prevent this evolution. COLONOSCOPY is the most common method for detecting and removing intestinal polyps.