So you followed doctor’s orders and got a colonoscopy at the age of 50 and you now have your results. If no polyps or other abnormalities are found, congratulations! You will likely be told to come back in 10 years for a follow-up exam. Keep following your current healthy lifestyle by eating plenty of vegetables and salads, minimize your red meat intake, and keep exercising. However, if you have been diagnosed with colon polyps, what do these results mean?
The colonoscopy procedure is performed by looking at the inner walls of the colon (also called the large intestine) through a fiberoptic camera. During the procedure, your doctor will remove any polyps or other abnormal areas and send this tissue to a pathologist for microscopic inspection and definitive diagnosis. The pathologic diagnosis is then used to determine what kind of follow-up you require to minimize the chances of developing colorectal cancer. This risk is determined based on any family history of polyps or colorectal cancer as well as the number, type, and size of the polyps found.
Common Types of Colon Polyps
The most common type of colon polyp is the hyperplastic polyp. This type of polyp has no real chance of progressing to cancer.
The adenoma is the next most common type of colon polyp and is divided into various subtypes. All adenomas are considered precancerous. The World Health Organization has divided adenomas into two general pre-cancerous risk categories – those with low-grade dysplasia and those with high-grade dysplasia. The term ‘dysplasia’ refers to abnormal growth of cells (from the Greek dys- ‘bad’ + plasis ‘formation’). The vast majority of adenomas fall into the low-grade category and have a low risk of progression to cancer. However, any diagnosis of high-grade dysplasia in an adenoma increases your risk for colorectal cancer and requires more frequent clinical surveillance. You may need to have additional studies or even surgery performed if you are diagnosed with high-grade dysplasia in a colon polyp, depending on the extent of dysplasia, the polyp size, and other factors.
Sessile serrated polyps are another type of fairly common colon polyp. They look similar microscopically to hyperplastic polyps, but have an increased chance of progressing to colorectal cancer, especially with increasing size. Some serrated polyps have low- or high-grade dysplasia in them. These carry an even higher risk of colorectal cancer.
Less Common Types of Colon Polyps
Inflammatory/post-inflammatory-type polyps are almost always benign and likely just a local reaction to tissue damage. There may be one or multiple of these polyps, depending on their underlying cause.
Juvenile polyps may be single or multiple, inherited or sporadic. They may be associated with an inherited syndrome called Juvenile Polyposis and the polyps may contain areas of precancerous (dysplastic) change.
Peutz-Jeghers polyps have a distinctive appearance under the microscope with a core that looks like the branches of a tree. Other types of sporadic polyps can be found at any age. There are other less common and unusual types of polyps, but those discussed above cover the vast majority of what will be found endoscopically.