An abnormal growth of tissue protruding from the lining of a mucus membrane such as the intestine (bowel). They can occur in any part of the gastrointestinal tract but are commonest in the large intestine (colon and rectum). There are many different types of polyps. Of particular concern areĀ  adenomatous polyps, which over time, may become malignant leading to the development of bowel cancer. They usually cause no symptoms and are detected at colonoscopy or at bowel cancer screening.