gastric lymphoma is a general term for a type of cancer that originates within the stomach. Approximately 90 percent of patients of primary gastric lymphoma are either mucosa-associated lymphoid tissue (MALT) gastric lymphoma or diffuse large B-cell lymphoma (DLBCL) of the stomach. MALT gastric lymphoma is often associated with infection with the Helicobacter pylori bacterium. Within the medical literature, significant controversy exists regarding the exact definition, classification and staging of primary gastric lymphoma.The term lymphoma refers to cancer that arises in the lymphatic system. Functioning as part of the immune system, the lymphatic system helps to protect the body against infection and disease. It consists of a network of tubes known as lymph vessels that drain a thin watery fluid known as lymph from different areas of the body into the bloodstream. Lymph collects in the tiny spaces between tissue cells and contains proteins, fats, and certain white blood cells known as lymphocytes. As lymph moves through the lymphatic system, it is filtered by a network of small structures known as lymph nodes that help to remove microorganisms (e.g., viruses, bacteria, etc.) and other foreign bodies from the bloodstream.