This factsheet is about MALT lymphoma – a slow-growing type of non-Hodgkin lymphoma. It most commonly develops in the stomach (gastric MALT lymphoma) but can develop in other parts of the body (non-gastric MALT lymphoma). Contents: What is MALT lymphoma?; Who gets it?; Symptoms; Diagnosis and staging; Outlook; Treatment; Follow-up; Relapsed and refractory MALT lymphoma; Research and targeted treatments.