Colorectal polyp

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

(Polyp of sigmoid colon as revealed by colonoscopy. Approximately 1 cm in diameter. The polyp was removed by snare cautery)

Symptoms

Colorectal polyps are not usually associated with symptoms. When they occur, symptoms include rectal bleeding, bloody stools, abdominal pain and fatigue. A change in bowel habits may occur including constipation and diarrhoea. Occasionally, if a polyp is big enough to cause a bowel obstruction, there may be nausea, vomiting and severe constipation.

(Gross appearance of a colectomy specimen containing two colorectal polyps and one invasive colorectal carcinoma.)

Screening and 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.

Treatment

Polyps can be removed during a colonoscopy or sigmoidoscopy using a wire loop that cuts the stalk of the polyp and cauterises it to prevent bleeding. Many "defiant" polyps — large, flat, and otherwise laterally spreading adenomas — may be removed endoscopically by techniques that involve injection of fluid underneath them, to lift them and thus enable them to be taken out. These techniques, when they may be employed, are an alternative to a much-more-invasive colectomy.

Structure

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