Introduction

Definition of stomach polyps

Polyps are defined as irregular tissue growths. Gastric polyps are abnormal tissue growths that project from the mucosal lining of the stomach.¹ These polyps are also considered lesions that protrude into the stomach lumen. Gastric polyps are found in about 6% of patients in Western countries.² There are several different types of gastric polyps, each with its own distinct cause and origin.

Types of stomach polyps

Hyperplastic polyps

Hyperplastic polyps are caused by increased inflammation in the foveolar cells of the stomach, which are responsible for producing mucin that protects the stomach’s inner surface. Due to the abnormal growth of foveolar cells in the polyp, the gastric pit (part of the stomach lining) becomes elongated and causes elevations in the lining of the stomach.

Description

Hyperplastic polyps are often multiple in number. Their typical size ranges from 0.5 to 1.5 cm in diameter. They have a smooth, dome-shaped appearance and are often found in the antrum, the lower part of the stomach. Sometimes these polyps can get larger and more lobulated so the membrane gets eroded, leading to chronic blood loss and in turn, iron deficiency anemia.

Frequency and risk factors

Gastric hyperplastic polyps are caused by either Helicobacter pylori infection (a type of bacteria that infects the stomach) or by an autoimmune disease affecting the stomach, such as autoimmune gastritis. However, recent studies have found that hyperplastic polyps can also occur in normal gastric mucosa (stomach lining). Patients who suffer from large hyperplastic polyps may experience obstruction of the stomach outlet. Gastric hyperplastic polyps can also arise when there are ulcers or erosions in the stomach lining. They affect both genders equally and are most commonly found in people between the ages of 60 and 70.³

Fundic gland polyps

Fundic gland polyps affect the fundic glands in the stomach, which are responsible for secreting gastric fluid.

Description

Fundic gland polyps are typically small, around 1 cm in diameter, and often appear in multiple numbers. They have a glossy, smooth, and leaf-like shape.

Frequency and risk factors

Fundic gland polyps are the most common type of gastric polyps in Western Europe, the United States, and Canada. Studies have shown that prolonged use of proton pump inhibitors, such as Prilosec and Nexium, can lead to the development of fundic gland polyps. These polyps are rarely found in patients with an existing H. pylori infection.³

Adenomatous polyps (Adenomas)

Adenomatous polyps are a type of neoplastic polyp (abnormal masses of tissue that increase in size very fast). They are the most common type of gastric neoplastic polyps.

Description

Adenomas have a lobulated, velvety appearance. Unlike the two types of polyps mentioned earlier, gastric adenomas are typically solitary rather than multiple. Gastric adenomas can be found at any site in the stomach, though they are usually located in the antrum.

Frequency and risk factors

Gastric adenomas often arise due to H. pylori infection and intestinal metaplasia (a change in the nature or type of a cell). They can also develop in the presence of chronic atrophic gastritis. Gastric adenomas may progress to gastric carcinoma. The larger the size of the polyp, the higher the risk of it developing into a carcinoma.

In Western countries, gastric adenomas caused by H. pylori infection are rare, accounting for approximately 1% of cases. While in East Asian regions, gastric adenomas comprise about 25% of gastric polyps. The chances of encountering gastric adenomatous polyps are equal in both men and women. Their frequency increases in people in their sixties and seventies.³

Other types

Inflammatory fibroid polyps

Inflammatory fibroid polyps, also known as Vanek tumors, are very rare lesions. They are typically asymptomatic, but the larger polyps can cause abdominal pain, anaemia, and gastric outlet obstruction. Inflammatory fibroid polyps are usually single, firm, and often ulcerated.³

Causes and risk factors

Gastric polyps are commonly associated with:

• Helicobacter pylori infection
• Pernicious anaemia (an autoimmune disorder caused by a severe deficiency in vitamin B12)
• Hypochlorhydria (low levels of stomach acid, specifically hydrochloric acid)
• Achlorhydria (the stomach does not secrete hydrochloric acid due to a certain condition or disorder)
• Atrophic gastritis (a condition in which inflammation causes the stomach lining to become very thin)

Helicobacter pylori infection

Helicobactor pylori infection is a very common infection worldwide. The incidence of this infection varies by geographic region, with higher rates observed in areas with low socioeconomic status. This is often due to overcrowding, which makes individuals more susceptible to infection and transmission. Studies have shown that the number of infections either remains constant or increases due to recurrence and failure to completely eradicate the infection.

Here are some causes of H. pylori infection:

1. A patient who had an endoscopic procedure to eradicate an early gastric cancer
2. Undiagnosed dyspepsia (discomfort in the upper abdomen) 
3. Prolonged use of aspirin
4. Prolonged use of non-steroidal anti-inflammatory drugs
5. Untreated iron deficiency anemia⁴

Successful eradication of H. pylori infection can lead to the regression and disappearance of gastric polyps.⁵

Chronic gastritis 

Chronic gastritis (inflammation of the stomach) is a serious, lifelong condition. Almost all of the world’s population suffers from it to varying degrees. Chronic gastritis can lead to gastric polyps, peptic ulcers, and eventually cancer.⁶

Familial adenomatous polyposis (FAP)

Familial adenomatous polyposis is a type of autosomal dominant disease caused by a mutation in one of the 22 pairs of chromosomes. It leads to the development of thousands of adenomas in the colon and the rectum, typically occurring in patients in their twenties. This condition also causes fundic gland polyps in the stomach. Almost all cases of familial adenomatous polyposis result in colorectal cancer if not treated at an early stage.⁷

Use of proton pump inhibitors (PPIs)

Proton pump inhibitors are drugs used to decrease acid secretion in the stomach by acting on the parietal cells. Prolonged use of proton pump inhibitors can lead to complications, including the development of fundic gland polyps in the stomach.⁸

Age and gender

Non-malignant stomach polyps usually occur in people over 50 years old, with a similar prevalence in both men and women.

Diet and lifestyle

Many unhealthy lifestyle behaviours can negatively affect gut and stomach health, and potentially cause stomach polyps. Unhealthy habits include eating quickly, consuming hot foods, and having a low intake of fruits and fibre. High consumption of red meat is also associated with the development of stomach polyps. Red and processed meat and hot drinks can lead to gastric polyps and cancer, especially in old people. Therefore, healthy foods and warm drinks are recommended.⁹

Symptoms

Asymptomatic nature of many polyps

Almost 50% of gastric polyps show no symptoms.

Possible Symptoms

Abdominal pain

Nausea and vomiting

Bleeding

Bleeding can be minimal, appearing in the stool, or it can be more significant, manifesting as vomiting blood or internal bleeding in the upper gastric tract. While bleeding is more common with large polyps, a small polyp that becomes ulcerated can also cause bleeding.

Anemia

Anaemia is a symptom of gastric polyps and may be accompanied by bleeding. It is usually due to iron deficiency resulting from decreased absorption or repeated bleeding.

Treatment and management

The treatment of gastric polyps depends on several factors, including the underlying cause of the polyp, its size, and the risk of malignancy. Eradicating the underlying cause can lead to successful treatment of the polyp. Discontinuing proton pump inhibitors have shown regression in fundic gland polyps. Successful eradication of H. pylori infection leads to the regression of hyperplastic polyps. Polypectomy or resection of the polyp is usually performed when the polyp is larger than 1 cm or when it causes gastric obstruction.¹⁰ The muscles of the stomach are thick, so the chances of perforation and bleeding during polypectomy are low.

Summary

Stomach polyps are small, irregular tissue growths that arise in the stomach for several reasons and come in various types. Gastric polyps can be caused by H. pylori infection, prolonged use of proton pump inhibitors, familial adenomatous polyposis, chronic gastritis, or lifestyle factors and age. Most polyps are asymptomatic, but some can cause symptoms such as abdominal pain, bleeding, and anaemia. Treatment of the polyps depends on their size and underlying cause, as some polyps carry a risk of turning into cancer.