Sessile serrated polyp of the large intestine

By Jason Wasserman MD PhD FRCPC
May 20, 2025

A sessile serrated polyp (SSP) is a non-cancerous growth found in the colon. Although SSPs themselves are not cancer, they are considered precancerous because they have the potential to develop into a type of colon cancer called adenocarcinoma over time. Doctors typically recommend completely removing SSPs to prevent them from turning cancerous.

Sessile serrated polyps are also known as sessile serrated lesions (SSL) or sessile serrated adenomas (SSA). All three terms describe the same precancerous condition.

Where are sessile serrated polyps usually found?

SSPs most commonly occur on the right side of the colon, including areas called the cecum, ascending colon, and transverse colon. However, SSPs can develop anywhere in the colon or rectum.

Does a sessile serrated polyp mean cancer?

No, an SSP does not mean you have cancer. However, because these polyps are precancerous, they can become a type of colon cancer called adenocarcinoma over time if left untreated. Completely removing an SSP significantly lowers the risk of it progressing to cancer.

What is the difference between a sessile serrated polyp and other types of polyps?

In pathology, a polyp refers to any growth that sticks out from the tissue surface. An SSP is one specific type of polyp. However, not all polyps are SSPs. Other common types of polyps in the colon and rectum include:

• Tubular adenomas: Polyps that may develop into cancer over time.

• Tubulovillous adenomas: Polyps that have features of both tubular and villous adenomas.

• Villous adenomas: Polyps with a higher risk of turning cancerous.

• Hyperplastic polyps: Generally non-precancerous polyps.

• Traditional serrated adenomas: Precancerous polyps similar to SSPs, but with distinct microscopic features.

How is the diagnosis of sessile serrated polyp made?

Doctors typically diagnose an SSP after it is removed during a colonoscopy. The polyp may be removed in a single piece or in several smaller fragments. The tissue is then carefully examined by a pathologist under a microscope.

SSPs can sometimes be challenging to detect during a colonoscopy. They often appear flat and subtle and blend with the colon’s lining, making them difficult to identify and remove completely.

What is a sessile serrated polyp with dysplasia, and why is dysplasia important?

Dysplasia refers to an area of abnormal cell growth within a polyp, indicating a higher risk for developing colon cancer. When colon cancer arises from an SSP, it usually starts in an area showing dysplasia. Due to this increased cancer risk, pathologists carefully check SSPs for signs of dysplasia.

In the past, dysplasia was sometimes classified as low grade or high grade, but this is no longer recommended. Now, any dysplasia identified in an SSP is considered important, often leading your doctor to recommend closer follow-up.

While all SSPs require complete removal, the presence of dysplasia may prompt an earlier repeat colonoscopy, especially if the initial removal was incomplete.

What is a margin?

A margin is the edge or boundary where a polyp (including an SSP) is cut and removed from the colon or rectum. Pathologists usually do not specify if an SSP was completely removed because this is best determined by the doctor performing the colonoscopy.

Because SSPs are often removed in fragments, it might be difficult or impossible for pathologists to clearly identify the true margin. Therefore, margins may not be specifically mentioned in the pathology report.

However, if cancer cells are identified within an SSP, the pathology report should clearly state how close the cancer is to the margin. This information is important for determining any further treatment.

What is the risk of developing cancer with a sessile serrated polyp?

Most SSPs will never turn into cancer. However, SSPs have a higher cancer risk than certain other types of polyps, such as hyperplastic polyps. The actual risk depends on factors like the size of the polyp, how long it has been present, and whether dysplasia is present. Typically, larger SSPs (greater than one centimeter) or those with dysplasia have a higher chance of becoming cancerous. Doctors recommend complete removal and regular follow-up colonoscopies to manage this risk effectively.

Can a sessile serrated polyp grow back after being removed?

If an SSP is completely removed during a colonoscopy, it usually does not regrow. However, if parts of the SSP are left behind, there is a chance it could return. Because SSPs can be difficult to visualize and remove fully, doctors typically recommend regular follow-up colonoscopies after removal to ensure that no polyp has regrown and to detect any new growths.

Questions to ask your doctor

If your pathology report mentions a sessile serrated polyp (SSP), you may want to ask your doctor:

• Was my SSP completely removed during the colonoscopy?

• Did the SSP show any dysplasia?

• When should my next colonoscopy be scheduled?

• How can I lower my risk of developing colon cancer in the future?

Understanding the term sessile serrated polyp can help you actively participate in your healthcare and ensure clear communication with your medical team.