Regression of Gastroduodenal Mucosa‐Associated Lymphoid Tissue Lymphoma after Eradication of Helicobacter pylori: A Case Report

Increasing evidence suggests that eradication therapy of Helicobacter pylori (H. pylori) may be an effective treatment for gastric lymphoma of mucosa‐associated lymphoid tissue (MALToma), but it remains unclear whether a similar therapeutic effect may be obtained for MALToma at other sites. We describe here a case of regression of gastroduodenal MALToma after eradication therapy for H. pylori. A 39‐year‐old man underwent gastroscopy at a routine check‐up, which demonstrated protruding lesions like a raised erosion in the antrum and multiple whitish granular lesions in the fornix. Simultaneously, multiple coarse nodular lesions were also found in the duodenal bulb. Forceps biopsy specimens obtained from both the stomach and bulb showed infiltration of small‐ to medium‐sized lymphocytes with cleaved nuclei, centrocyte‐like cells, together with atypical large lymphoid cells into the glandular lesion, and the rearrangement of immunoglobulin was positive, thereby allowing diagnosis of low grade MALToma with large cell transformation. H. pylori was positive in the stomach, while the presence of H, pylori was not detected microscopically in the bulb, although ectopic gastric mucosa was identified in the bulb. Regression of multiple coarse or granular lesions in both the stomach and bulb were observed three months after eradication of H. pylori. Thereafter the disappearance of MALToma was verified histologically a further six months later. There was no recurrence of MALToma detected over a two‐year follow‐up period. These findings suggest that eradication of H. pylori could be a treatment of first choice for MALToma occurring in the gastrointestinal tract outside the stomach.