Causes

Stomach polyps form in response to damage to your stomach lining. The most common causes of stomach polyps are:

• Chronic stomach inflammation. Also known as gastritis, this condition can cause the formation of hyperplastic polyps and adenomas. Hyperplastic polyps are unlikely to become cancerous, although those larger than about 2/5 inch (1 centimeter) carry a greater risk.

  Adenomas are the least common type of stomach polyp but the type most likely to become cancerous. For that reason, they are generally removed.

• Familial adenomatous polyposis. This rare, inherited syndrome causes certain cells on the stomach's inner lining to form a specific type of polyp called fundic gland polyps. When associated with this syndrome, fundic gland polyps are removed because they can become cancerous. Familial adenomatous polyposis can also cause adenomas.

• Regular use of certain stomach medications. Fundic gland polyps are common among people who regularly take proton pump inhibitors to reduce stomach acid. These polyps are generally small and aren't a cause for concern.

  Fundic gland polyps with a diameter larger than about 2/5 inch (1 centimeter) carry a small risk of cancer, so your doctor might recommend discontinuing proton pump inhibitors or removing the polyp or both.