Colon Villous Adenoma at 20x Magnification
Villous adenomas and other polyps rarely present symptoms except in very advanced cases. When they do occur, however, they may include abnormal bleeding, cramps, abdominal pain, constipation, or diarrhea. Polyps in the rectum are occasionally palpable by rectal examination, but more often require examination via endoscopy to be discovered. Thus, individuals who are at an elevated risk of developing colonic polyps are generally advised to undergo regular screening in order that adenomas and other benign tumors may be detected before they grow to significant sizes, in which case they are associated with a higher rate of malignant change. Screening techniques that are commonly utilized include stool specimen tests for occult blood, which is blood that cannot be seen by the unaided eye, and flexible sigmoidoscopy, which involves the insertion of a tubular instrument into the anus in order that the lower portion of the colon can be visualized.