A stomach biopsy can reveal a wide range of conditions, from common bacterial infections to early-stage cancer. During an upper endoscopy, a doctor takes small tissue samples from the stomach lining and sends them to a pathologist, who examines the cells under a microscope. The results can identify infections, inflammation, precancerous changes, polyps, and tumors that wouldn’t be visible any other way.
H. Pylori Infection
One of the most common reasons for a stomach biopsy is to check for Helicobacter pylori, the bacterium responsible for most stomach ulcers and a major driver of chronic gastritis. The pathologist looks for the spiral-shaped bacteria nestled in the stomach lining, often using special stains to make them easier to spot. A standard stain detects H. pylori in roughly 60 to 80 percent of cases, but more targeted staining methods push accuracy to 90 or even 100 percent.
A rapid urease test is sometimes performed alongside the biopsy. This test checks whether the tissue produces a chemical reaction associated with the bacterium, and it reaches about 90 percent sensitivity with 95 to 100 percent specificity. When both methods are used together, the chances of missing an active infection drop significantly. Confirming H. pylori matters because eradication with antibiotics can heal ulcers, reduce inflammation, and lower long-term cancer risk.
Gastritis and Its Subtypes
Gastritis simply means inflammation of the stomach lining, but a biopsy tells the story behind it. The pathologist grades the inflammation by looking at which immune cells are present, where they’ve gathered, and how much damage they’ve caused. “Chronic active gastritis” means both long-standing inflammation and an ongoing flare, often signaled by white blood cells called neutrophils infiltrating the glands and forming small abscesses in the tissue.
Autoimmune gastritis looks different under the microscope. It’s characterized by heavy infiltration of certain immune cells into the gland lining itself, clusters of immune tissue at the base of the stomach wall, and a notable increase in a type of white blood cell called eosinophils. Nearly 93 percent of autoimmune gastritis cases show thickening of the muscle layer beneath the glands, and about 87 percent display irregular gland architecture. These features help the pathologist distinguish autoimmune gastritis from other types, which matters because autoimmune gastritis can lead to vitamin B12 deficiency and requires different monitoring.
Chemical gastritis, caused by bile reflux or long-term use of anti-inflammatory medications, tends to show a distinct pattern called foveolar hyperplasia, where the tiny pits on the stomach surface become elongated and twisted.
Precancerous Changes
A biopsy can catch cellular changes that haven’t become cancer yet but raise the risk of developing it over time. The two key findings here are intestinal metaplasia and dysplasia.
Intestinal metaplasia means the normal stomach lining has been replaced by cells that resemble the lining of the intestine, complete with specialized “goblet” cells that don’t belong in the stomach. This transformation is part of a well-documented progression: chronic gastritis leads to tissue loss (atrophy), which leads to intestinal metaplasia, which can progress to dysplasia, and eventually to cancer. Catching it at the metaplasia stage gives you and your doctor time to increase surveillance and address risk factors like an untreated H. pylori infection.
Dysplasia is a step further along that path. It means the cells have started to look abnormal in ways that suggest they’re moving toward cancerous behavior, even though they haven’t invaded surrounding tissue yet. The pathologist grades dysplasia as low or high, and high-grade dysplasia typically prompts more aggressive follow-up or removal of the affected tissue.
Atrophy and Gland Loss
Atrophy refers to the loss of the stomach’s specialized glands. This can be tricky to identify on a biopsy, especially when metaplasia has already replaced the missing glands with different cell types. Pathologists grade atrophy on a visual scale: mild means less than 30 percent of glands are lost, moderate is 31 to 60 percent, and marked atrophy means more than 60 percent are gone. Significant atrophy reduces your stomach’s ability to produce acid and absorb certain nutrients, and it’s a recognized risk factor for stomach cancer.
Stomach Polyps
Polyps are small growths on the stomach lining that are usually discovered during endoscopy and then biopsied to determine their type. The two most common kinds are fundic gland polyps and hyperplastic polyps, and they carry very different implications.
Fundic gland polyps are the most frequently found type and are strongly associated with long-term use of proton pump inhibitors (acid-reducing medications like omeprazole). In people without an inherited genetic syndrome, these polyps rarely turn cancerous.
Hyperplastic polyps are a different story. They’re linked to chronic gastritis and H. pylori infection, and they can harbor malignant cells, particularly when they grow larger than 5 to 10 millimeters. That’s why larger hyperplastic polyps are usually removed entirely rather than just sampled. If H. pylori is present, treating the infection can sometimes cause these polyps to shrink or disappear and reduces the chance of recurrence.
Stomach Cancer
A biopsy is the only definitive way to diagnose stomach cancer. The pathologist examines the tissue for malignant cells and, if cancer is found, determines the type. The most common form is adenocarcinoma, which arises from the gland cells of the stomach lining. Less common types include lymphoma (cancer of immune tissue in the stomach wall), neuroendocrine tumors, and gastrointestinal stromal tumors.
When adenocarcinoma is confirmed, the pathologist runs additional tests on the tissue. One critical test checks for overproduction of a protein called HER2, which is present in a subset of stomach cancers and makes them eligible for a specific targeted therapy. The report also notes features like how deeply the cancer has grown, whether it has spread into nerves, and whether it arose within a pre-existing benign growth.
Getting enough tissue matters for an accurate cancer diagnosis. British Society of Gastroenterology guidelines recommend at least eight biopsy samples when advanced cancer is suspected. For a gastric ulcer being checked for possible malignancy, six samples is the standard recommendation, yet audits have found that only about 18 percent of such cases actually receive that many. If your biopsy results are inconclusive and cancer hasn’t been definitively ruled out, asking about a repeat procedure with more samples is reasonable.
What Your Pathology Report Might Say
Pathology reports use standardized language that can be confusing at first glance. Here are some of the most common terms and what they mean in practical terms:
- Chronic active gastritis: Long-standing inflammation with signs of an ongoing flare. Often associated with H. pylori.
- Atrophy (mild, moderate, or marked): Loss of the stomach’s normal glands, graded by the percentage lost.
- Intestinal metaplasia: Normal stomach cells have been replaced by intestinal-type cells. A precancerous change that warrants monitoring.
- Foveolar hyperplasia: The surface pits of the stomach lining are overgrown and twisted, often from chemical irritation.
- Dysplasia (low-grade or high-grade): Cells that look abnormal and are on a trajectory toward cancer. High-grade is more urgent.
- Negative for malignancy: No cancer cells found in the samples examined.
After the Biopsy
A stomach biopsy is performed during an upper endoscopy, which typically takes 15 to 30 minutes. You’re sedated for the procedure, and the actual tissue sampling is painless. Results usually take a few days to a couple of weeks, depending on the lab and whether special stains or additional testing are needed.
Recovery is straightforward. You should take it easy for the rest of the day, and you won’t be able to drive or make major decisions for 24 hours due to the lingering effects of sedation. Most people can eat within a few hours, starting with soft foods and working back to their normal diet as comfort allows. Mild bloating or a sore throat from the scope is common and resolves quickly.