Hyperplastic polyp of the stomach

What is a hyperplastic polyp in the stomach?

A hyperplastic polyp is a non-cancerous growth that develops from the tissue that lines the inside of the stomach. Most hyperplastic polyps in the stomach are associated with a condition called chronic gastritis or prolonged inflammation in the stomach. The most common causes of chronic gastritis are infection of the stomach with Helicobacter pylori, bile reflux, and autoimmune gastritis.

Continue reading to learn more about the stomach and your pathology report for hyperplastic polyp.

The stomach

The stomach is part of the gastrointestinal tract. When we eat, food enters the mouth and travels down the esophagus into the stomach. Once in the stomach, the food is mixed with a strong acid which breaks the food down into very small particles. This process is called digestion. The digested food particles are then either absorbed into the bloodstream or removed from the body as waste.

The tissue on the inner surface of the stomach is made up of specialized epithelial cells that form a barrier called the epithelium. The cells at the top of the epithelium are called foveolar cells and they protect the stomach from the strong acid used to break down food. Underneath the surface epithelium is a thin layer of tissue called the lamina propria which supports the surface cells. Together, the surface epithelium and lamina propria are called the mucosa.

How do pathologists make the diagnosis of a hyperplastic polyp?

The diagnosis of hyperplastic polyp is usually made after part or all of the polyp is removed during a procedure called endoscopy. This procedure involves using a camera attached to a long tube to see the inside of the stomach. The tissue removed is then sent to a pathologist for examination under the microscope.

When examined under the microscope, hyperplastic polyps show an increased number of foveolar cells which makes epithelium look disorganized. Large open or dilated spaces may also develop. The connective tissue or stroma surrounding the foveolar cells usually shows signs of inflammation including an increased number of inflammatory cells such as plasma cells, lymphocytes, and neutrophils.

Because hyperplastic polyps can be caused by infection of the stomach with a bacteria called Helicobacter pylori, your pathologist may perform tests such as special stains or immunohistochemistry to look for the bacteria in the tissue sample. Both of these tests make it easier to see the bacteria which are very small and difficult to see on a hematoxylin and eosin-stained (H&E) slide.

Intestinal metaplasia

Long-standing inflammation or chronic gastritis that is not treated can damage the foveolar epithelium. If the damage continues for many years, a new type of epithelium similar to the epithelium normally found in the small intestine slowly replaces the foveolar epithelium.

The change from foveolar type epithelium to small intestinal-type epithelium is an example of metaplasia and pathologists describe the specific type of metaplasia that takes place in the stomach as intestinal metaplasia. Intestinal metaplasia may be found in some hyperplastic polyps. If your pathologist sees intestinal metaplasia in the tissue sample, it will be described in your report.


Pathologists use the word dysplasia to describe cells showing an abnormal pattern of growth. Like intestinal metaplasia, dysplasia can develop in patients who have had chronic gastritis for many years.

Dysplasia is not typically seen in a hyperplastic polyp but when seen it will be described in your report. Pathologists divide dysplasia into low and high grades based on how abnormal the tissue looks when examined under the microscope.

Dysplasia is a non-cancerous change. However, it is considered a precancerous condition because it increases the risk of developing a type of stomach cancer called adenocarcinoma over time. The risk of cancer is higher with high-grade dysplasia.

Syndromes associated with hyperplastic polyps

For most patients, hyperplastic polyps are unrelated to any preexisting genetic condition. Some patients, however, inherit genetic changes that put them at a higher risk of developing multiple hyperplastic polyps as well as other non-cancerous growths.

These patients are said to have a syndrome and the most common syndromes associated with hyperplastic polyps are Peutz-Jeghers, Cowden, and Juvenile polyposis.

In these syndromes, specific genes that normally prevent our cells from growing and dividing too rapidly or in an uncontrolled way, are altered or mutated. This causes uncontrolled cell growth and the development of a non-cancerous polyp.

by Jason Wasserman, MD FRCPC (updated December 23, 2021)
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