What Is a Sessile (Stalkless) Polyp? What You Need to Know

Polyps are groups of cells that develop in the tissues of different organs, from the nose to the colon. Polyps may have a stalk or be stalkless. Stalked polyps grow on stalks, whereas stalkless polyps lie flat in a dome-like shape.

Polyps are abnormal growths arising from the mucosa, the tissue lining that covers the surface of many internal organs. Polyps often occur in the bladder, stomach, nose, gallbladder, and cervix, but are most commonly found in the colon.

Among adults, 20 – 30% develop colon polyps. They are usually benign, but may sometimes be cancerous. For this reason, monitoring polyps is important, and in some cases complete removal may be the best approach.

- Related topic: What Is a Polyp, and How Should Large Bowel Polyps Be Treated?

What is a sessile (stalkless) polyp?

A sessile polyp is a flat mass that forms in the mucosal layer of a hollow organ in the body. These polyps grow flat on the tissue lining the organ and may gradually blend into it. This inconspicuous appearance makes them difficult to find and treat.

Sessile polyps are generally precancerous (noncancerous but with the potential to become cancer), meaning that cancer may develop in them. However, they may be either benign or cancerous. Colonoscopy can detect them, and they can usually be removed to prevent the risk of cancer developing.

- Related topic: What to Know Before a Colonoscopy – Preparation

Polyps may also have stalks. Rather than the flat dome shape of sessile polyps, stalked polyps extend on stalks. This structure gives them a mushroom-like appearance.

Types of sessile polyps

Common types of sessile polyps;

• Hyperplastic
• Sessile serrated
• Tubular (tube-shaped)
• Tubulovillous

Each of these four categories has the potential to develop into colorectal cancer, but sessile serrated polyps have the greatest potential.   

The sessile serrated form is one of three categories of serrated polyps. Of these categories, the sessile serrated polyp is the most difficult to identify and remove. It is also the type most likely to become cancerous. Sessile serrated polyps are the most common and tend to carry the lowest risk of being cancerous unless they contain major cellular changes. However, if they show signs of dysplasia, they have substantial cancer potential.

Causes and risk factors

There are various theories about why sessile polyps can develop.

Research suggests that sessile serrated polyps result from a combination of a mutation in a gene called BRAF and a process called supportive hypermethylation. Put simply, the mutant gene causes cells to divide, which the body cannot prevent.

Certain risk factors make people more likely to develop colon polyps. These risk factors differ slightly among types of sessile polyps. For example, people are more likely to develop sessile serrated polyps if they have the following factors;

• Aged 50 or older
• Male
• African American
• A history of inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease
• Not exercising regularly
• Obesity
• High red meat consumption
• A fiber-free diet
• Tobacco use

Many risk factors and causes are similar among polyp categories but differ in the strength of their effects. Genetic factors also play a role.

- Related topic: The Relationship Between Obesity and Cancer

Symptoms of sessile polyps

Most of the time, sessile polyps cause no symptoms. Unfortunately, in such cases doctors may discover the polyps only during a medical examination or colonoscopy. In some cases, however, polyps in the colon may cause symptoms such as;

• Abdominal pain
• Changes in bowel movements
• Blood in the stool

Diagnosis of sessile polyps

A colonoscopy may be performed to identify polyps in the colon. During this procedure, the specialist examines the large bowel and part of the small bowel with a colonoscope.

An effective camera on a tube that allows the colon walls to be seen, a colonoscope enables specialists to confirm the presence of polyps. Also, the flatter sessile polyps are, the more difficult they are to identify.

In addition, a biopsy involving tissue removal may be performed to determine the type of polyps and whether they have the potential to become cancerous.

Treatment of sessile polyps

Sessile polyps may not always require treatment. If they are found to be harmful, they may not be removed, but should be monitored regularly.

People with a history of polyps have a greater risk of developing polyps in the future and even of those polyps being cancerous. We therefore recommend that these individuals have general health screenings more frequently.

If polyps are cancerous or have the potential to become cancerous, we recommend removing them. If they are accessible, polypectomy is a method that can be used to remove them during a colonoscopy.

Different surgical techniques may be used to remove polyps during a colon polypectomy. Among the options, cold forceps polypectomy, hot forceps polypectomy and snare polypectomy are included.

- Related topic: How Often Should Colon Cancer Be Followed Up by Colonoscopy After Polypectomy?

If the polyps are cancerous at diagnosis and the cancer has spread, the person may need radiation therapy or chemotherapy.

Cancer risk for sessile polyps

Polyps are classified as neoplastic or non-neoplastic (not neoplastic). Non-neoplastic categories generally cause less concern because they do not have the potential to become cancerous. In contrast, identifying neoplastic variations is important because they can lead to colorectal cancer.

Sessile serrated polyps are an example of neoplastic polyps. They are among the most concerning polyp types because a person may live for years without knowing that sessile serrated polyps are present. During this time, unmonitored polyps may develop into cancer.

When should you see a doctor?

Because polyps generally cause no symptoms, regular general health checkups are important. A biopsy may be taken so that specialists can check for polyps and determine their likelihood of becoming cancerous.

Summary

A sessile polyp is a flat or dome-shaped mass extending from the mucosal layer of hollow organs. These polyps may be neoplastic or non-neoplastic (not neoplastic). Because neoplastic polyps have the potential to become cancerous, diagnosis by a doctor and removal if necessary are important.

Polyps may develop in different parts of the body but occur most commonly in the colon. They are especially common in people aged 50 and older. Because they generally cause no symptoms, regular general health checkups are important to maximize the chances of early diagnosis and good outcomes.

- Related topic: Colon and Rectal Cancer Symptoms, Stages, and Treatment