Stomach Cancer Types

The most common type of stomach cancer is known as an adenocarcinoma. Adenocarcinoma is responsible for about 90 percent of all cases of stomach cancer.

Adenocarcinoma is a type of cancer that originates in glandular tissue. Specifically, it originates in a type of glandular tissue known as epithelial tissue, which lines the surfaces and cavities of the body's organs. As all our organs are lined with epithelial tissue, adenocarcinomas can affect any organ where epithelial tissue is present, not just the stomach.

Adenocarcinoma of the stomach originates in the cells that form the innermost layer of the stomach in the mucus producing cells, called the mucosa.

Stomach Cancer Types: Rare Cancers

While adenocarcinoma is the most common type of stomach cancer, it is not the only type. There are other, rarer types of stomach cancer, and the treatment and prognosis differ from adenocarcinomas.

Other types of stomach cancer may include:

• Gastric lymphomas: These are cancers of the immune system tissue located in the stomach. The immune system protects the body against infection and disease.
• Gastrointestinal stromal tumors: Also known as GIST, these types of stomach tumors can be benign (noncancerous) or cancerous. They form from cells in the stomach wall called interstitial cells of Cajal, a type of smooth muscle tissue. 
• Carcinoid tumors: These stomach tumors are a rare, slow-growing type of cancer that originates in the cells of the nervous system and endocrine system.