Regression of duodenal mucosa-associated lymphoid tissue lymphoma after eradication of Helicobacter pylori.

It is rare for low-grade lymphoma of mucosa-associated lymphoid tissue (MALT) to affect the duodenum, and no reports have mentioned any relationship between this disease and Helicobacter pylori infection. This case report describes a patient with multiple small erosions and diffuse erythema in the duodenal bulb diagnosed histopathologically as MALT lymphoma. Immunoglobulin (Ig) heavy-chain gene rearrangement was detected, and monotypic plasma cell proliferation (IgG kappa) was shown by immunohistochemistry. The lesion was localized to the duodenal bulb. Antibiotic therapy for H. pylori resulted in resolution of the morphological features of the lymphoma, as confirmed by endoscopic and pathological examination. Moreover, the gene rearrangement could not be detected after eradication of the bacterium. Although additional follow-up is needed, it is suggested that H. pylori eradication therapy may be effective for patients with MALT lymphoma in the duodenum as well as the stomach.