Polyps of the Colon and Rectum

Most polyps are asymptomatic. Rectal bleeding, usually occult and rarely massive, is the most frequent complaint.

Cramps, abdominal pain, or obstruction may occur with a large lesion.

Rectal polyps may be palpable by digital examination. Occasionally, a polyp on a long pedicle may prolapse through the anus.

Large villous adenomas may rarely cause watery diarrhea that may result in hypokalemia Hypokalemia Hypokalemia is serum potassium concentration < 3.5 mEq/L (< 3.5 mmol/L) caused by a deficit in total body potassium stores or abnormal movement of potassium into cells. The most common... read more .

Diagnosis of colonic polyps is usually made by colonoscopy. Barium enema, particularly double-contrast examination, is effective, but colonoscopy is preferred because polyps also may be removed during that procedure. Because rectal polyps are often multiple and may coexist with cancer, complete colonoscopy to the cecum is mandatory even if a distal lesion is found by flexible sigmoidoscopy.

During colonoscopy, any polyps seen are removed and evaluated for possible cancer.

Polyps should be removed completely with a snare or biopsy forceps during total colonoscopy. If colonoscopic removal is unsuccessful, laparotomy should be done.

Subsequent treatment depends on the histology of the polyp. If dysplastic epithelium does not invade the muscularis mucosa, the line of resection in the polyp’s stalk is clear, and the lesion is well differentiated, endoscopic excision and close endoscopic follow-up should suffice. Patients with deeper invasion, an unclear resection line, or a poorly differentiated lesion should have segmental resection of the colon. Because invasion through the muscularis mucosa provides access to lymphatics and increases the potential for lymph node metastasis, such patients should have further evaluation (as in colon cancer Colorectal Cancer Colorectal cancer is extremely common. Symptoms include blood in the stool and change in bowel habits. Diagnosis is by colonoscopy. Treatment is surgical resection and chemotherapy for nodal... read more ).

The scheduling of follow-up examinations after polypectomy is controversial and varies by the number, size, and type of polyps removed (1 Treatment reference An intestinal polyp is any mass of tissue that arises from the bowel wall and protrudes into the lumen. Most are asymptomatic except for minor bleeding, which is usually occult. The main concern... read more ). For example, guidelines recommend a repeat total colonoscopy (or barium enema if total colonoscopy is impossible) 3 years after removal of a tubular adenoma ≥ 10 mm or a villous adenoma of any size.

Aspirin and COX-2 inhibitors may help prevent formation of new polyps in patients with polyps or colon cancer (1 Prevention reference An intestinal polyp is any mass of tissue that arises from the bowel wall and protrudes into the lumen. Most are asymptomatic except for minor bleeding, which is usually occult. The main concern... read more ). The potential benefits of long-term therapy with these agents must be weighed against the potential adverse effects (eg, bleeding, renal dysfunction).

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