The short answer
More than 9 in 10 stomach cancers are adenocarcinomas. Rarer types, including GIST, neuroendocrine tumors, and lymphoma, start in different cells and need different treatment.
More than 9 in 10 stomach cancers are adenocarcinomas.
Adenocarcinoma has two subtypes: intestinal, which has a better outlook, and diffuse, which is harder to treat.
Gastrointestinal stromal tumors (GISTs) start in different cells and are treated with targeted drugs.
Neuroendocrine tumors often grow slowly, though some can be aggressive.
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The full explanation.
The simple version
Most stomach cancer is one type, called adenocarcinoma. A small share of stomach tumors start in other cells. Those are treated very differently.
Adenocarcinoma: the common type
More than 9 in 10 stomach cancers are adenocarcinomas. They start in the gland cells lining the stomach. There are two main patterns:
- Intestinal type. Cells form gland-like structures. This pattern generally has a somewhat better outlook.
- Diffuse type. Cells look more abnormal. They tend to spread through the stomach wall instead of forming one clear lump. That makes this type harder to treat.
Other, rarer types
- Gastrointestinal stromal tumors (GISTs). Uncommon tumors that are thought to begin in cells of the stomach wall called interstitial cells of Cajal. They are treated with targeted drugs, not standard chemotherapy.
- Neuroendocrine tumors (NETs), sometimes called carcinoids. These start in cells that act partly like nerve cells and partly like hormone-making cells. Most grow slowly.
- Lymphomas. Cancers that start in white blood cells. They usually begin elsewhere, but can begin in the stomach wall.
- Other rare types. Squamous cell carcinoma, small cell carcinoma, and leiomyosarcoma can start in the stomach, but they are very uncommon.
In short: adenocarcinoma is the great majority of cases. The rarer types need their own treatment plans.
Why type matters for treatment
A GIST, a lymphoma, and an adenocarcinoma of the stomach are three very different diseases. They just happen to start in the same organ. A biopsy and pathology review confirm the exact type. That shapes everything that follows. It sets which drugs are used, and what surgery, if any, is advised. Even within adenocarcinoma, knowing the intestinal or diffuse subtype helps your team set realistic expectations.
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Common questions
What is the most common type of stomach cancer?
Adenocarcinoma is by far the most common type, making up more than 9 in 10 stomach cancers. It starts in the gland cells of the stomach lining.
What is the difference between intestinal and diffuse adenocarcinoma?
Intestinal adenocarcinoma has gland-like structures under the microscope and generally has a better outlook. Diffuse adenocarcinoma looks more abnormal, tends to spread through the stomach wall rather than forming a distinct lump, and is generally harder to treat.
What is a GIST?
A gastrointestinal stromal tumor (GIST) is an uncommon tumor that starts in specialized cells in the stomach wall called interstitial cells of Cajal. GISTs are treated very differently from adenocarcinoma, often with targeted drugs rather than standard chemotherapy.
Can lymphoma start in the stomach?
Yes, though it's uncommon. Lymphomas usually start in lymph nodes elsewhere in the body, but some start in the stomach wall. These are treated like lymphomas, not like typical stomach cancer.
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Last updated: 2026-08-11Next planned review: 2027-08-03
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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