Gastric low-grade mucosal-associated lymphoid tissue-lymphoma: Helicobacter pylori and beyond

The stomach is the most frequently involved site for extranodal lymphomas, accounting for nearly two-thirds of all gastrointestinal cases. It is widely accepted that gastric B-cell, low-grade mucosal-associated lymphoid tissue (MALT)-lymphoma is caused by Helicobacter pylori (H. pylori) infection. MALT-lymphomas may engender different clinical and endoscopic patterns. Often, diagnosis is confirmed in patients with only vague dyspeptic symptoms and without macroscopic lesions on gastric mucosa. H. pylori eradication leads to lymphoma remission in a large number of patients when treatment occurs at an early stage (I-II(1)). Neoplasia confined to the submucosa, localized in the antral region of the stomach, and without API2-MALT1 translocation, shows a high probability of remission following H. pylori eradication. When both bacterial infection and lymphoma recur, further eradication therapy is generally effective. Radiotherapy, chemotherapy and, in selected cases, surgery are the available therapeutic options with a high success rate for those patients who fail to achieve remission, while data on immunotherapy with monoclonal antibodies (rituximab) are still scarce. The 5-year survival rate is higher than 90%, but careful, long-term follow-up is required in these patients since lymphoma recurrence has been reported in some cases.