Colonic mucosa is a term used to describe the specialized tissue that covers the inside of the colon. The colon is a long, hollow organ and part of the digestive tract. It starts at the end of the small bowel (the ileum) and ends at the anal canal. Colonic mucosa is made up of specialized epithelial cells that connect together to form glands and a thin layer of connective tissue called the lamina propria.
A wide variety of medical conditions may involve the colonic mucosa. For example, most types of colonic polyps including tubular adenomas, tubulovillous adenomas, villous adenomas, and sessile serrated adenomas all start from the cells in the colonic mucosa. The most common type of colon cancer, called adenocarcinoma, also starts from cells in the colonic mucosa. Inflammatory, auto-immune conditions such as Crohn’s disease, ulcerative colitis, and microscopic colitis also involve this tissue. Your doctor may remove a small sample of colonic mucosa in a procedure called a biopsy to look for any of these conditions, along with other conditions that may involve the inner surface of the colon.