by Jason Wasserman MD PhD FRCPC
August 2, 2023
A foveolar type adenoma is a non-cancerous growth that starts from cells on the inside surface of the stomach. It is a rare type of polyp in the stomach although it is slightly more common in people with familial adenomatous polyposis (FAP) syndrome and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) syndrome.
Most foveolar type adenomas are found in the body (fundus) of the stomach.
These adenomas are called foveolar type because they are made up of specialized foveolar cells that are normally found on the inside surface of the stomach.
Most foveolar type adenomas of the stomach do not cause any symptoms although large adenomas may bleed which can cause abdominal pain or a change in bowel habits.
Foveolar type adenomas of the stomach are more common in people with familial adenomatous polyposis (FAP) syndrome and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) syndrome. In this context, the adenoma is caused by genetic changes that allow cells in the stomach to grow faster than normal cells. Doctors do not know what causes foveolar adenomas in people without an underlying genetic syndrome.
When examined under the microscope, a foveolar type adenoma is made up of abnormal cells that resemble the specialized foveolar cells found on the inside surface of the stomach. Similar to normal foveolar cells, the cells in the adenoma contain neutral mucin that can be highlighted with a special stain called PAS. The abnormal cells have dark elongated nuclei that often overlap with nearby cells. This type of growth is also called a polyp because it sticks out from the surface of the tissue.
All foveolar 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 a foveolar 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 foveolar 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 foveolar type adenomas. If left untreated, foveolar types adenomas with high grade dysplasia can turn into a type of stomach cancer called adenocarcinoma. If possible, all 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 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 foveolar 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, a foveolar 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).