They can be either benign growths or malignant growths. The malignant growths can either have primary or secondary causes. Adenomatous polyps are considered precursors to cancer and cancer becomes invasive once malignant cells cross the muscularis mucosa and invade the cells below. Any cellular changes seen above the lamina propria are considered non-invasive and are labeled atypia or dysplasia. Any invasive carcinoma that has penetrated the muscularis mocos has the potential for lymph node metastasis and local recurrence which will require more aggressive and extensive resection. The Haggitts criteria is used for classification of polyps containing cancer and is based on the depth of penetration. The Haggitts criteria has level 0 through level 4, with all invasive carcinoma of sessile polyp variant by definition being classified as level 4. Level 0: Cancer does not penetrate through the muscularis mucosa. Level 1: Cancer penetrates through the muscularis mucosa and invades the submucosa below but is limited to the head of the polyp. Level 2: Cancer invades through with involvement of the neck of polyp. Level 3: Cancer invades through with involvement of any parts of the stalk. Level 4: Cancer invades through the submucosa below the stalk of the polyp but above the muscularis propria of the bowel wall. Adenomas
Neoplastic polyps of the bowel are often benign hence called adenomas. An adenoma is a tumor of glandular tissue, that has not (yet) gained the properties of cancer.The common adenomas of the colon (colorectal adenoma) are the tubular, tubulovillous, villous, and sessile serrated (SSA).
People are often diagnosed with Peutz-Jegher after presenting at around the age of 9 with an intussusception. The polyps themselves carry little malignant potential but because of potential coexisting adenomas there is a 15% chance of colonic malignancy. Juvenile polyps are hamartomatous polyps that often become evident before twenty years of age, but can also be seen in adults. They are usually solitary polyps found in the rectum which most commonly present with rectal bleeding. Juvenile polyposis syndrome is characterised by the presence of more than five polyps in the colon or rectum, or numerous juvenile polyps throughout the gastrointestinal tract, or any number of juvenile polyps in any person with a family history of juvenile polyposis. People with juvenile polyposis have an increased risk of colon cancer. Inflammatory polyp
These are polyps that are associated with inflammatory conditions such as ulcerative colitis and Crohns disease. Prevention
Diet and lifestyle are believed to play a large role in whether colorectal polyps form. Studies show there to be a protective link between consumption of cooked green vegetables, brown rice, legumes, and dried fruit and decreased incidence of colorectal polyps. Diagnosis
Colorectal polyps can be detected using a faecal occult blood test, flexible sigmoidoscopy, colonoscopy, virtual colonoscopy, digital rectal examination, barium enema or a pill camera.Malignant potential is associated with

degree of dysplasia
Type of polyp (e.g.