Gastric polyps are small growths that form on the inner lining of your stomach. They’re found in roughly 1% to 6% of people who undergo an upper endoscopy, and the vast majority are harmless. Most people never know they have them because they rarely cause symptoms. They’re typically discovered by accident when a doctor examines your stomach for an unrelated reason.
Not all gastric polyps are the same, though. The type you have determines whether it’s worth monitoring, removing, or simply ignoring.
The Three Main Types
Gastric polyps fall into three major categories, each with different causes and levels of concern.
Fundic Gland Polyps
These are the most common type in Western countries and the least worrisome. They form from the glands that produce stomach acid and are made up of dilated glands containing the cells normally found in that part of the stomach. They’re small, often multiple, and carry essentially no cancer risk in people without a genetic polyposis syndrome. Current guidelines suggest removing fundic gland polyps only when they reach 1 cm or larger.
Hyperplastic Polyps
These are the second most common type and tend to develop in stomachs that are already inflamed, particularly from a Helicobacter pylori infection. Under a microscope, they show elongated, branching glands sitting in swollen tissue. They’re more common in parts of the world where H. pylori infection rates are high. Guidelines recommend removing hyperplastic polyps that are 0.5 cm or larger, partly because a small percentage can harbor precancerous changes.
Adenomatous Polyps
These are the rarest of the three but the most clinically significant. Adenomatous polyps contain abnormal cells that already show at least early-stage dysplasia, meaning the cells have begun changing in ways that can lead to cancer. Because of this risk, guidelines recommend removing adenomatous polyps of any size. They come in several subtypes based on the kind of cells involved, but the key point is the same: all of them need to come out.
What Causes Them
The causes vary by type, but two factors dominate: acid-suppressing medications and bacterial infection.
Long-term use of proton pump inhibitors (PPIs), the class of drugs that includes omeprazole and similar heartburn medications, is strongly linked to fundic gland polyps. In one study, 23% of patients taking PPIs had fundic gland polyps compared to 12% of non-users. The risk climbs with duration: five or more years of PPI use was associated with a fourfold higher risk. These polyps have little clinical significance on their own, but if you’ve been on a PPI for years and polyps show up on an endoscopy, the medication is the likely explanation.
H. pylori infection is the primary driver behind hyperplastic polyps. Studies have found that anywhere from 37% to 79% of patients with hyperplastic polyps have evidence of current or past H. pylori infection. The good news is that treating the infection often makes these polyps disappear. Research has shown that over 70% of hyperplastic polyps vanish completely within 7 to 10 months after the bacteria are eliminated.
Genetics play a role in some cases. Up to 90% of people with familial adenomatous polyposis (FAP), an inherited condition that causes widespread polyp growth in the colon, also develop stomach polyps. Only about 1% of those stomach polyps become cancerous, but the sheer number of them requires ongoing monitoring.
Symptoms and How They’re Found
Most gastric polyps cause no symptoms at all. When they do, it’s usually because they’ve grown large or started bleeding.
Bleeding from a gastric polyp happens inside the digestive tract, so you won’t feel it. The first sign is often a change in your stool: bleeding from the upper digestive tract typically produces black, tarry stools rather than bright red ones. If the bleeding is slow and persistent, it can gradually cause iron-deficiency anemia, leaving you pale, weak, and unusually tired.
Rarely, a polyp grows large enough to block the pylorus, the narrow opening at the bottom of your stomach where food passes into the small intestine. This can cause nausea, indigestion, and stomach pain. But this scenario is uncommon. The vast majority of polyps are small and silent.
Because symptoms are so rare, most polyps are discovered incidentally during an endoscopy performed for something else, like investigating heartburn, ulcers, or unexplained abdominal pain.
How Doctors Tell Them Apart
During an endoscopy, the doctor can often get a preliminary sense of what type of polyp they’re looking at using advanced imaging techniques. Narrow-band imaging (NBI) uses filtered light to highlight the surface pattern and blood vessel structure of a polyp. Fundic gland polyps, for instance, tend to appear the same color or lighter than the surrounding tissue and show a distinctive lacy vessel pattern. When those features are present, the chance that the polyp is actually an adenoma or cancer is essentially zero.
Still, visual assessment alone isn’t definitive. A biopsy, where the doctor snips a small tissue sample or removes the polyp entirely, is the standard way to confirm the type. The tissue goes to a pathologist who examines it under a microscope and looks for the specific cell patterns that distinguish one type from another.
Cancer Risk by Type
The cancer question is what most people really want answered, and the news is mostly reassuring.
Fundic gland polyps carry virtually no cancer risk in people without an inherited polyposis syndrome. They’re considered benign, and most doctors won’t even biopsy small ones if the appearance is clearly typical.
Hyperplastic polyps have a small but real risk. A tiny percentage can develop dysplasia, particularly when they’re large. This is one reason guidelines recommend removing any that are 0.5 cm or bigger.
Adenomatous polyps carry the highest risk. Data from patients with FAP who were followed over time shows that the 10-year cumulative incidence of gastric cancer was 1% among those with polyps overall, but jumped to 6% in those with low-grade dysplasia and 20% in those with high-grade dysplasia. Polyps larger than 2 cm had an 11% ten-year cancer incidence. These numbers underscore why adenomatous polyps are removed regardless of size and why follow-up endoscopy is standard after removal.
Treatment and Removal
Most gastric polyps don’t need treatment. Small fundic gland polyps, for example, are typically left alone. If you’re on a PPI and fundic gland polyps appear, your doctor may discuss whether the medication is still necessary, though the polyps themselves rarely warrant stopping a drug you need.
When removal is indicated, it’s done during an endoscopy. The doctor passes a thin, flexible tube with a camera and tools through your mouth and into your stomach, then snips or shaves the polyp off the stomach wall. This is an outpatient procedure, and recovery is quick. The removed tissue is sent for analysis to confirm the type and check for any precancerous changes.
For hyperplastic polyps linked to H. pylori, treating the infection is often the most effective approach. A course of antibiotics to clear the bacteria can cause the polyps to regress or disappear entirely, sometimes eliminating the need for endoscopic removal.
Less Common Gastric Polyps
Beyond the three main types, a few rarer growths can appear in the stomach. Inflammatory fibroid polyps are benign lesions that typically develop in the lower part of the stomach (the antrum). They’re most common in adults around age 60, tend to measure between 1 and 3 cm, and have no risk of becoming cancerous. Small ones are often found incidentally, while larger ones can occasionally cause abdominal pain, bleeding, or anemia.
These rare types are worth mentioning because they can look similar to more concerning polyps during an endoscopy. Biopsy is the only reliable way to distinguish them, which is another reason doctors routinely sample polyps that look unusual.