Non-cancerous tumours of the stomach

A non-cancerous (benign) tumour of the stomach is a growth that does not spread (metastasize) to other parts of the body. Non-cancerous tumours are not usually life-threatening. They are typically removed with surgery and do not usually come back (recur).

There are many types of non-cancerous tumours of the stomach but most are rare.

Gastric polyps are the most common non-cancerous stomach tumours. A gastric polyp is a growth that develops in the lining of the stomach. Polyps may look like a mushroom with a head and a stalk (called pedunculated polyps). They may also be flat and grow along the inner surface of the wall of the stomach (called sessile polyps).

Some gastric polyps may develop gastric epithelial dysplasia( a precancerous condition). This makes them more likely to develop into cancer, but the risk of them changing into cancer is still low.

There are several types of gastric polyps:

• fundic gland polyps – usually smaller than 1 cm and may occur by chance or happen in people with polyposis syndromes
• hyperplastic polyps – typically smaller than 2 cm and are often found in people with an inflamed stomach (gastritis)
• inflammatory fibroid polyps – hard, red, swollen (inflamed) and can grow large enough to cause a blockage
• xanthoma – a fatty, yellowish growth that is usually smaller than 3 mm
• hamartomatous polyps – surrounded by normal stomach lining and may occur by chance or in people with polyposis syndromes

Polyposis syndromes are inherited (genetic) conditions where large numbers of polyps develop in the gastrointestinal (GI) tract, usually the colon or small intestine. Benign gastric polyps can occur in the following polyposis syndromes:

• Peutz-Jeghers syndrome
• juvenile polyposis
• Cowden syndrome
• Cronkhite-Canada syndrome
• Gardner syndrome
• familial adenomatous polyposis (FAP)

Other types of non-cancerous stomach tumours are rare. These include:

• a gastrointestinal stromal tumour (GIST)– small GISTs may be non-cancerous but larger ones are often cancerous
• a lipoma – made up of fat cells
• a leiomyoma – made up of smooth muscle cells
• tumours of the peripheral nerves, such as schwannoma and neurofibroma
• an ectopic pancreas (pancreatic heterotopia) – made up of pancreatic tissue cells
• a hemangioma – made up of abnormal blood vessels
• a lymphangioma – develops in lymph vessels
• a glomus tumour (perivascular tumour) – develops from cells around blood vessels
• a fibroma – made up of fibrous tissue
• a mucocoele – develops when a mucus-releasing gland becomes blocked

Gastric polyps may develop because of an inherited condition or in areas of the stomach that are inflamed or damaged. Fundic gland polyps may also develop in people who take drugs that lower the amount of acid made in the stomach (such as proton-pump inhibitors). But we don’t know what increases the risk for other non-cancerous stomach tumours because they are so rare.

Non-cancerous stomach tumours rarely cause signs and symptoms. Most tumours are found accidentally when an upper gastrointestinal endoscopy is done for other reasons. Signs and symptoms may appear if the polyp grows very large and may include:

• upper abdominal pain
• bleeding
• anemia
• gastric outlet obstruction (blocked opening from the stomach to the small intestine)
• digestive problems, such as nausea and vomiting or feeling full after a small meal (early satiety)
• lump in the abdomen (if the tumour is large)

Non-cancerous stomach tumours are usually discovered when a person has tests done for other reasons. If you have symptoms or your doctor thinks you might have a non-cancerous stomach tumour, you will be sent for tests. Tests used to diagnose or rule out non-cancerous stomach tumours include:

• an upper gastrointestinal endoscopy
• an endoscopic ultrasound
• an endoscopic biopsy

The standard treatment for non-cancerous stomach tumours is surgery. The type of surgery mostly depends on the size of the tumour and includes the following:

• an endoscopic biopsy – to remove polyps that are smaller than 2 cm
• a gastrostomy – a cut (incision) in the stomach wall to remove polyps larger than 5 cm or many flat polyps
• a stomach resection – to remove a small tumour along with a margin of healthy tissue
• a gastrectomy – removing all or part of the stomach (for many polyps)

Some people with polyposis syndromes may need several treatments to remove polyps. You may not have treatment if a tumour is smaller than 1 cm and isn’t causing any signs or symptoms. But you may need to have regular checkups with an endoscopy to see if it grows or starts to look different.