Regression of CD5-positive and Helicobacter pylori-negative mucosa-associated lymphoid tissue lymphoma of the rectum after administration of antibiotics: report of a case.

We report a case of mucosa-associated lymphoid tissue lymphoma of the rectum that regressed after antibiotics administration. A 70-year-old female complained of abdominal discomfort. Colonoscopy performed in July 1998 showed a hemispheric protrusion of the rectum, the surface of which was covered with normal rectal mucosa. Pathologic diagnosis of a biopsy specimen was low-grade mucosa-associated lymphoid tissue lymphoma. Gastroscopy showed multiple erosions of the antrum, and was negative by both culture and histology. After informed consent the patient was treated with a 14-day course of lansoprazole, amoxicillin, and clarithromycin for the eradication of. Repeat colonoscopy ten days after initiation of treatment showed that the rectal tumor had disappeared, and this was confirmed by histologic examination. There was no recurrence during 20 months of follow-up.