Sessile polyps are growths of the colon wall that are considered to be precancerous lesions. You may ask ‘What are sessile polyps?’ They are growths of cells that are flat appearing. They do not protrude very far into the center of the lumen of the colon. The term sessile polyp in colon is used instead of tubular polyp or pedunculated polyp. A tubular polyp is one that has a more tube-like appearance. It extends further in the center of the colon. The pedunculated polyp is one that has a stalk. It also is easier to see on the wall of the colon because it sticks out further than a sessile polyp. The fact that the polyp is more flat than it is protuberant causes some problems. The larger the polyps, the easier they are to find and take out. If they blend in with the rest of the colon tissue, they are harder to identify and
A sessile polyp in colon occurs when cells of the innermost layer begin to divide rapidly and grow. These cells normally divide faster that the rest of the cells in the body since they form a layer called an epithelia. An epithelial layer is one that exists to protect the inside workings of the body from the outside. Even though the colon lies within the abdomen, the stool and all of the material that a person eats is treated as though it is outside the body. Therefore the epithelia have to provide a barrier function against these elements. Because epithelia are constantly exposed to toxins and other agents, they need to be replaced on a regular basis in order to maintain the integrity of the layer. Other tissues are not replaced like this. For example, neurons of the brain do not divide and replace each other, neither do the kidney are heart cells. Only the cells of the skin, GI tract and blood are constantly turning over to make new copies.
In the process of constantly creating new copies of the cells, some errors can be made in the DNA. The mechanism of copying the DNA is not always perfect. So when the layers of the colon are replicated, it is possible for a mutation to occur. As the mutations builds up and expands, it can form a sessile polyp colon. There are other ways of developing mutations. Some times people have genetic issues in their family that increase the rest of mutations. Other times a person can have been exposed to radiation or chemotherapy. These agents have devastating effects on the replication of cells and cause them to develop a lot of different mutations.
Now people can answer the question ‘What are sessile polyps’ with some degree of certainty. Because they have the potential to grow into a cancer, the polyps need to be removed. That is why there are screening programs for colon cancer in existence and people should get a colonoscopy. If the sessile polyps are removed before they get to big and start to invade other tissue, a person can be saved from colon cancer.