Colonic Polyps with Case

00:01 We'll move on to our next case.

00:03 We have a 59-year-old woman who undergoes a routine screening called colonoscopy.

00:08 On colonoscopy, she is found to have a 15 mm polyp in the descending colon and no other lesions.

00:16 The polyp is removed.

00:18 Pathology shows a villous adenoatous polyp.

00:21 She asks how these findings relate to her risk of developing colorectal cancer.

00:27 So how should she be counseled and is this a lesion with malignancy potential? Let's go to some key features here.

00:35 So, she has a large polyp which is probably a high risk.

00:40 And she has a villous adenoma on her pathology.

00:43 We'll talk a bit more about what that means.

00:48 So we categorize colonic polyps in 2 different ways.

00:52 First, their gross appearance on endoscopy.

00:55 And second, by histology.

00:57 So first let's focus on their appearance You may have a sessile polyp, which is when you have a polyp and majority of its base is attached to the colonic wall as shown here.

01:09 You may also have a pedunculated polyp.

01:12 This is when the polyp is attached by a short stalk to the colonic wall.

01:19 And lastly, you may have a flat polyp.

01:21 These are as you can imagine, some of the most difficult polyps you detect.

01:25 as there is not much to distinguish it from the rest of the colonic wall.

01:31 Next, we also categorize polyps based on their appearance on histology.

01:36 So you may have an adenomatous polyp which is usually just a benign growth of tubular glands that grow from the colonic wall.

01:45 You may have a serrated polyp.

01:47 which is a typical sawtooth like appearance of the glands on histology.

01:52 And you may have other types of histologic polyps including hamartomas and other things that we will not cover here.

02:01 So some higher risk features of polyps include larger size, so specifically anything larger than or equal to 10 millimeters.

02:10 The histologic type of anomalous polyp tends to be the highest risk.

02:15 Those that have high degrees of dysplasia as seen on histology are also at elevated risk.

02:23 And lastly, a sessile shape can also be a high risk feature.

02:28 So if you have any pf these high risk features, these polyps should be removed.

02:33 And patients who have those should be surveilled with colonoscopy at more frequent intervals than the normal.

02:41 So now let's talk a bit more in detail about adenomatous polyps.

02:46 Within that broad category of adenomatous polyps, there are different types of histology that are more worrisome than others.

02:53 So first is a tubular adenoma.

02:56 This is when the majority of the polyp is made up of branching tubules as shown here.

03:01 It is the most common, about 80% of all adenomas are this type.

03:07 You may also have a tubulovillous adenomatoma which is a mixed picture between tubular and villous.

03:15 This makes up about 15% of all adenomas.

03:19 The last category is a villous adenoma.

03:23 In this, you have the majority of long glands that then extend to the center.

03:28 And this again, is about 15% of adenomas.

03:31 This is important because as you go from tubular, to tubulovillous and lastly to villous, you have increasing risk of malignancy.

03:39 So villous adenoma is the highest risk of progressing to malignancy.

03:46 So treatment of colonic polyps typically consist of complete removal of the polyp and then considering surveillance colonoscopy on follow up.

03:55 How often you do surveillance colonoscopy depends on the number of factors including: size, the number of polyps that were found, and the histology of the polyps.

04:07 So now we can return to our case.

04:09 We had a 59-year-old woman undergoing routine screening colonoscopy.

04:14 She has a large polyp that's greater than 10 mm in size - so that is a high risk feature.

04:19 In addition, she has villous adenoma histology which is as we know now, also at high risk for dysplasia.

04:28 So how should she be counseled and is this a lesion with malignancy potential? We now know that based on the size and the histology of her polyp, this is now a high-risk polyp that was removed so she now needs more frequent surveillance colonoscopy, you might consider repeating one in 3 years.