This type is a mixture of tubular and villous adenomas, with characteristics of each. Villous adenomas are usually larger and more likely to be cancerous. This type of adenoma sprawls out like the fronds of a fern, a sign of faster and more chaotic growth. They’re typically smaller in size and less worrisome. These adenomas look like tiny tubes jammed into your colon lining. There are three kinds of adenomas, which doctors can determine by looking under a microscope. What is an adenoma?Īdenomas are polyps made from tissue that looks like the usual lining of your colon but isn’t.
Polyps with cells that look only mildly abnormal are labeled as having low-grade dysplasia and are of less concern. “It’s a finding that warrants increased attention,” notes Dr. Your healthcare provider may recommend a follow-up colonoscopy sooner than normal if they find polyps with high-grade dysplasia. These dysplastic cells often grow wildly, a sign that cancer may have been close to forming in the polyp. Polyps with signs of high-grade dysplasia have disorganized cells with a larger, darker center. The review is to determine levels of dysplasia, a term used to describe how cancerous polyps appear on a cellular level. They’re the most challenging to remove and sometimes difficult to locate.ĭoctors examine removed polyps under a microscope for a close-up look at their cells. Flat polyps are the least common polyps, making up about 2% of discovered lesions.Cancer can develop on the head of pedunculated polyps. (Think of a cherry on a stem.) They’re easy to spot and can usually be removed in one piece during a colonoscopy. Pedunculated polyps hang from a stalk attached to your colon wall.Sessile polyps can be snared and removed somewhat easily in a colonoscopy, though larger ones are typically taken out in pieces. Sessile polyps are dome-shaped and grow flat on your colon wall.Polyps come in three basic shapes, says Dr. It’s estimated that it takes about 10 years for cancer to form into a colorectal polyp. As polyps slowly grow, however, the cancer risk rises. Studies show that few smaller polyps are cancerous. Larger polyps can be almost as big as the average person’s thumb. To put those sizes in perspective, a diminutive polyp is about the size of a match head. Polyps can range in size from the less-than-5-millimeter “diminutive” category to the over-30-millimeter “giants.” Why the size matters The smaller the polyp, the less likely it is to be on the road to cancer, says Dr. So, what’s the difference among polyps, and are some more worrisome than others? Dr. Finding and removing those polyps decreases your risk of developing the disease. Colorectal cancer begins in polyps, after all. They’re pretty common, especially in adults age 45 or older.īut that doesn’t mean polyps should be ignored, says colorectal surgeon Rebecca Gunter, MD. The vast majority of colorectal polyps are harmless growths that sprout on the lining of your colon or rectum. We do not endorse non-Cleveland Clinic products or services. Advertising on our site helps support our mission. Cleveland Clinic is a non-profit academic medical center.