Monoclonal gammopathy of undetermined significance predisposing to Helicobacter pylori-related gastric mucosa-associated lymphoid tissue lymphoma.

Gastric mucosa-associated lymphoid tissue (MALT)-associated B-cell proliferation may range from benign to malignant, and Helicobacter pylori is the only identified critical antigenic stimulus to the development of gastric MALT. Monoclonal gammopathy of undetermined significance (MGUS) is characterized by B-cell hyper-activation and clonal expansion and is know to predispose to B-cell malignancies. We report a patient with MGUS and H. pylori infection in whom we noted the progression of gastritis to acquired gastric MALT and gastric MALT to MALT lymphoma during a 3-year follow-up.