Colon polyps occur on the lining of the colon. While most colon polyps are benign, certain types develop into colon cancer. Middle-aged and older adults are more likely to have colon polyps. Further, the development of colon polyps increases with having a family or personal history of colon cancer or polyps, being overweight, eating a high-fat/low-fiber diet and smoking. The three major types of colon polyps are hyperplastic, adenomatous and inflammatory.
Hyperplastic
Hyperplastic polyps occur in the left (descending) colon. They measure less than 0.5 cm. Most hyperplastic polyps are benign and typically do not develop into colon cancer.
Adenomatous
The most common colon polyps are adenomatous. Adenomatous polyps have the capacity to turn malignant and cancerous. As the size of the adenomatous polyps increases, the likelihood that the polyp will turn cancerous increases. While only a small number of adenomatous polyps become cancerous, most malignant polyps are adenomatous. Three subtypes of adenomatous polyps exist. Microscopic characteristics determine subtype classifications. The subtypes are tubular, tubulovillous and villous (hairy).
Inflammatory
Inflammatory polyps stem from an episode of Crohn's diease of the colon or ulcerative colitis. The polyps are not a risk factor for colon cancer. However, the conditions of Crohn's disease of the colon and ulcerative colitis increases an individual's risk of colon cancer.
