by Jason Wasserman MD PhD FRCPC
August 1, 2023
An intestinal type adenoma is a non-cancerous growth that starts from cells on the inside surface of the stomach. It is the third most common type of polyp in the stomach after hyperplastic polyps and fundic gland polyps.
Most intestinal type adenomas are found in a part of the stomach called the antrum.
These adenomas are called intestinal type because they are made up of cells that look very similar to the cells in the small intestine.
Most intestinal type adenomas of the stomach do not cause any symptoms and patients usually seek medical attention for symptoms caused by related conditions such as Helicobacter pylori gastritis.
Any condition that causes intestinal metaplasia in the stomach can lead to the development of intestinal type adenomas. These conditions include long-standing infection of the stomach with Helicobacter pylori and autoimmune gastritis. Some genetic syndromes, for example, familial adenomatous polyposis syndrome (FAP), are also associated with an increased risk of developing intestinal type adenomas.
When examined under the microscope, an intestinal type adenoma is made up of abnormal cells that connect together to form long structures called tubules. The abnormal cells have dark elongated nuclei that often overlap with nearby cells. Large round cells called goblet cells are usually seen. These cells are not normally found in the intestine and their presence helps confirm that the adenoma is intestinal type. This type of growth is also called a polyp because it sticks out from the surface of the tissue.
All intestinal type adenomas of the stomach show an abnormal pattern of growth called dysplasia. Dysplasia is important because it is a precancerous change that can become cancerous over time. When examining an intestinal type adenoma, pathologists divide dysplasia into two levels: low grade dysplasia and high grade dysplasia.
Low grade dysplasia is an early precancerous change seen in most intestinal type adenomas. If left untreated, low grade dysplasia can change into high grade dysplasia or cancer over time. However, the overall risk is low.
High grade dysplasia is a more advanced precancerous change seen in a small number of intestinal type adenomas. If left untreated, intestinal types adenomas with high grade dysplasia can turn into a type of stomach cancer called adenocarcinoma. If possible, all intestinal type adenomas with high grade dysplasia should be removed completely.
A margin is any tissue that was cut by the surgeon in order to remove the intestinal type adenoma from your body. Dysplasia at the cut edge of the tissue means that the abnormal tissue may not have been completely removed from the body.
Some intestinal type adenomas grow on a piece of tissue called a stalk and the adenoma is removed by cutting the stalk. In these cases, the margin is the part of the stalk that is cut. However, most adenomas are removed and sent to pathology as multiple pieces (fragments) of tissue. In these cases, it may not be possible for your pathologist to determine which piece is the real margin and the changes seen at the margin will not be described in your report.
Yes, an intestinal type adenoma of the stomach can turn into cancer over time. However, for small adenomas and those showing only low grade dysplasia, the risk is very low. The risk is higher for larger adenomas, those showing high grade dysplasia, and for adenomas arising in a person for a genetic syndrome such as familial adenomatous polyposis (FAP).