Helicobacter pylori-positive Colorectal MALT Lymphoma with Repeated Metachronous Recurrence after a Complete Response to Eradication Therapy and Regression after a Watch-and-wait Strategy.

A 77-year-old man underwent a colonoscopy. A submucosal cecal tumor was found, and localized colorectal MALT lymphoma (Lugano stage I) was diagnosed with a Helicobacter pylori infection. The first-line eradication therapy was successful, and the cecal lesion regressed. However, a new lesion was observed in the lower rectum. The rectal lesion regressed after the second-line eradication therapy. Two new lesions were identified in the sigmoid colon. However, no additional treatment was administered and a watch-and-wait strategy was adopted. Both of the lesions regressed. There are no established treatments for colorectal MALT lymphomas. The watch-and-wait strategy may be effective in cases of recurrence after eradication therapy.