Gastric lymphoma This is a rare tumour, accounting for less than 5% of all gastric malignancies. The stomach is, however, the most common site for extranodal non-Hodgkin lymphoma and 60% of all primary gastrointestinal lymphomas occur at this site. Lymphoid tissue is not found in the normal stomach but lymphoid aggregates develop in the presence of H. pylori infection. Indeed, H. pylori infection is closely associated with the development of a low-grade lymphoma (classified as extranodal marginal-zone lymphomas of MALT type). EUS plays an impoant role in staging these lesions by accurately defining the depth of invasion into the gastric wall. The clinical presentation is similar to that of gastric cancer and endoscopically the tumour appears as a polypoid or ulcerating mass. While initial treatment of low-grade lesions confined to the superficial layers of the gastric wall consists of H. pylori eradication and close observation, 25% contain t(11:18) chromosomal translocations. In these cases, additional radiotherapy or chemotherapy is usually necessary. High-grade B-cell lymphomas should be treated by a combination of rituximab, chemotherapy , surgery and radiotherapy. The choice depends on the site and extent of tumour, the presence of comorbid illnesses, and other factors, such as symptoms of bleeding and gastric outflow obstruction. The prognosis depends on the stage at diagnosis. Features predicting a ourable prognosis are stage I or II disease, small resectable tumours, tumours with low-grade histology, and age below 60 years. Ref Davidson edition23rd pg805