COLONIC POLYPS

Masses protruding into gut lumen (sawtooth appearance), 90% are not neoplastic. Often in rectosigmoid. Adenomatous polyps are precancerous. Malignant risk is associated with increase size, villous histology, and increases epithelial dysplasia.

Patients with isolated colonic polyps are usually asymptomatic but can experience overt or occult colonic bleeding. Colonic polyps can occur as part of inherited polyposis syndromes in which their number is greater and the risk for malignant progression is much greater compared to the risk with isolated colonic polyps.

The more villous the polyp, the more likely it is to be malignant.

Hyperplastic: most common non-neoplastic polyps in colon (>50% found in rectosigmoid colon). They are usually less than 0.5 cm in diameter.

Thought previously to be entirely clinically insignificant, hyperplastic polyps are now recognized to possess some malignant potential in the setting of hyperplastic polyposis syndrome. Patients who are affected have an occurrence of hyperplastic polyps proximal to the sigmoid colon, with (1) 2 or more that are greater than 10 mm in diameter, (2) a total of more than 30 polyps, or (3) a first-degree relative with the syndrome. The polyps in this syndrome may have adenomatous components; display a serrated, saw-tooth surface epithelium; and harbor methylation of specific target genes, including mismatch repair genes.

Juvenile: mostly sporadic lesions in children <5 years old. 80% in rectum. If single, no malignant potential.

 

Juvenile polyposis syndrome: multiple juvenile polyps in GI system, increase risk of adenocarcinoma.

Peutz-Jeghers: Single polyps are not malignant.

Peutz-Jeghers syndrome: autosomal dominant syndrome featuring multiple nonmalignant hamartomas throughout GI tract, along with hyperpigmented mouth, lips, hands, and genitalia. Associated with increase risk of CRC and other visceral malignancies, patients with Peutz-Jeghers syndrome (PJS) have a 15-fold increased risk of developing intestinal cancer compared with that of the general population.