Biopsy samples collected from your colon or rectum are studied by a doctor with special training, called a pathologist. After testing the samples, the pathologist creates a report on what was found. Your doctor can then use this report to help manage your care.

The information here is intended to help you understand some of the medical terms you may see in your pathology report after your colon or rectum is biopsied.

Parts of the colon and rectum

The colon and rectum make up the large intestine (or colon), which is part of the digestive system. The appendix is the beginning of the large intestine, where the small intestine opens into the large intestine. The ascending colon, transverse colon, descending colonand sigmoid colon are the parts of the large intestine after the cecum. The large intestine ends at rectumwhere waste (faeces) is stored until it leaves the body through the anus.

Colon or rectal polyps

ONE polyp is a protrusion (growth) from the inner lining into the lumen (hollow center) of the colon or rectum.

There are different types of polyps that look different when viewed under a microscope. Most polyps are benign (non-cancerous) growths, but cancer can start in some types of polyps.

e.g. hyperplastic polyps are typically benign (not cancerous or pre-cancerous) and are not cause for concern. But the different types adenomatous polyps (adenomas)which are discussed below, are more of a concern because they can turn into cancer. These polyps can be seen as precursors to cancer, which is why it is important to remove them.

Types of adenomas

An adenoma (adenomatous polyp) is a type of polyp made up of tissue that looks a lot like the normal inner lining of your colon or rectum, although it’s different in some important ways when seen under a microscope.

There are different types of adenomas, which are often described in terms of their growth patterns.

Tubular, tubulovillous and villous adenomas

Adenomas can have 2 major growth patterns: tubular and villous. Many adenomas have a mixture of both growth patterns, so they are called tubular legal adenomas.

Most small adenomas (less than ½ inch) have a tubular growth pattern. Larger adenomas are more likely to have a villous growth pattern.

Larger adenomas and adenomas with a villous growth pattern are more likely to have cancer cells in them.

The growth pattern of a polyp can be important because it can help determine when you will need your next colonoscopy. But when a polyp is biopsied, the most important thing is that it is removed completely and that it does not show cancer.

Sessile polyps (sessile adenomas)

The expression stuck used to describe polyps that are slightly flattened and broad-based (as opposed to growing on a thin stalk).

Serrated polyps (serrated adenomas)

The blanket polyps (serrated adenomas) have a serrated appearance when viewed under a microscope. There are 2 types, which look slightly different:

• Sessile serrated adenomas (also called sessile serrated polyps)
• Traditional serrated adenomas

These types of polyps are not cancerous, but they are pre-cancerous (meaning they can turn into cancer) so they must be removed completely.

A person who has had a serrated polyp has an increased risk of later developing colon or rectal cancer. However, most people with these polyps never develop colon or rectal cancer.

Dysplasia

Dysplasia describes how much your polyp looks like cancer under a microscope:

• Polyps that are only mildly abnormal (doesn’t look much like cancer) are said to have low-grade (mild or moderate) dysplasia.
• Polyps that are more abnormal and look more like cancer are said to have high-grade (severe) dysplasia.

If high-grade dysplasia is found in your polyp, it may mean you need a repeat (follow-up) colonoscopy sooner than if it wasn’t found. But otherwise, dysplasia in a polyp is usually not a cause for concern.

The most important thing is that your polyp is completely removed and that it does not show cancer.

If an adenoma was not completely removed…

If you had an adenoma that was biopsied but not completely removed, talk to your doctor about what other treatment you may need.

Most often, adenomas are removed during a colonoscopy. Sometimes, however, an adenoma may be too large to be removed completely during the colonoscopy. If this is the case, you may need surgery to make sure the entire adenoma is removed.

Does having an adenomatous polyp (adenoma) affect my follow-up treatment?

If an adenoma was found during your biopsy, you’ll need another colonoscopy at some point to make sure you don’t have more adenomas. When you should have your next colonoscopy depends on a number of things, such as how many adenomas were found, if someone had a villous growth pattern, and if someone had high-grade dysplasia. Discuss the timing of your next colonoscopy with your doctor.