[A case of mucosa-associated lymphoid tissue lymphoma of the rectum].

We report a case of mucosa-associated lymphoid tissue (MALT) lymphoma of the rectum in a 67-year-old woman who was admitted to our hospital owing to bowel abnormalities. Colonoscopic examination revealed a submucosal tumor (SMT) in the lower rectum. However, no malignancy was found on rectal mucosa biopsy. After providing informed consent, the patient underwent transanal surgery for the SMT. Rectal MALT lymphoma was diagnosed based on results of histological and immunohistochemical examinations. According to the Lugano International Conference classification system, the present case was classified as stage I MALT lymphoma. After the operation, Helicobacter pylori infection occurred, for which eradication therapy was performed, but no further complications or recurrence occurred.