The difference between tubular and villous adenomas is the growth pattern of the polyp, which means that each type has differing growth shapes and looks different under a microscope, as the American Cancer Society details. Most polyps are small and have a tube-like growth pattern, but polyps can also be villous or display both growth patterns simultaneously, which leads to the development of a tubulovillous adenoma.
Larger adenomas, or those that have a villous growth pattern, are more likely to have cancers growing in them, as the American Cancer Society explains. A polyp is a non-cancerous growth that sticks out from the wall of the colon, and there are different types of polyps, including the adenoma. Adenomas have the potential to develop into cancer, which is why the growth pattern of the polyp is an important factor. Identifying the growth pattern helps physicians determine when more colonoscopies are necessary to check patients for additional polyp growth.
Another common term relating to polyps is "sessile," which is simply the medical term for a polyp that is flattened out with a broad base, according to American Cancer Society. A serrated polyp has a jagged or sawtooth appearance, and these require removal from the colon. A person with an adenoma must undergo another colonoscopy to ensure that more polyps do not develop. While most adenomas are removed during a colonoscopy, the adenoma is too large in some cases, which means that surgery is necessary to remove it.