What are Colorectal Polyps?

What are Colorectal Polyps?

A colorectal polyp is a polyp (fleshy growth) occurring on the lining of the colon or rectum. Untreated colorectal polyps can develop into colorectal cancer.

Colorectal polyps are often classified by their behaviour (i.e. benign vs. malignant) and/or etiology (e.g. as a consequence of inflammatory bowel disease).

They may be benign (e.g. hyperplastic polyp), pre-malignant (e.g. ) or malignant (e.g. colorectal adenocarcinoma).

Colorectal polyps are not usually associated with symptoms. Occasionally, if a polyp is big enough to cause a bowel obstruction, there may be nausea, vomiting and severe constipation.

Polyps are either pedunculated (attached to the intestinal wall by a stalk) or sessile (grow directly from the wall).

The most common general classification is:

• hyperplastic,
• adenomatous & malignant,
• hamartomatous and,
• inflammatory.

Neoplastic polyp

A neoplasm is a tissue whose cells have lost its normal differentiation. They can be either benign growths or malignant growths. The malignant growths can either have primary or secondary causes.

Neoplastic polyps of the bowel are often benign hence called adenomas. An adenoma is tumour of columnar cells or glandular tissue.

Neoplastic polyps can be further broken down into tubular, tubulovillous or villous. They are all broken down into these categories by histology (microscopic examination of tissue).

The villous subdivision is the worst because these have the greatest potential for malignancy. This is because the villi are projections into the lumen and hence have a bigger surface area and therefore a greater potential for malignant change.

Hamartomatous polyp

They are growths, like tumours found in organs as a result of faulty development. They are normally made up of a mixture of tissues. They grow at the normal rate of the host tissue and rarely cause problems such as compression. A common example of a hamartomatous lesion is a strawberry naevus. Hamartomatous polyps are often found by chance; occurring in syndromes such as Peutz-Jegher or Juvenile Polyposis Syndrome.

''Peutz-jeghers syndrome'' is associated with polyps of the GI tract and also increased pigmentation around the lips, genitalia, buccal mucosa feet and hands. 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 polyposis syndrome'' are polyps which often present when the patient is young hence called juvenile. Patients normally present young with rectal bleeding. Polyps can be solitary or multiple (>5). If there are multiple the condition is then referred to as Juvenile Polyposis. This condition may have a genetic association. Patients require upper and lower endoscopic screening with removal of polyps. If you fear adenomatous tissue developing then you can offer surgery, namely colectomy and ileorectal anastomosis

Inflammatory polyp

These are polyps which are associated with inflammatory conditions such as Ulcerative Colitis and Crohns disease.

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