Duodenal Mucosa-Associated Lymphoid Tissue Lymphomas: Two Cases and the Evaluation of Endoscopic Ultrasonography
A 52-year-old man visited with right upper quadrant pain. His physical examination, routine hematology, and biochemistry tests were normal. Endoscopy showed a depressed lesion with fold clubbing and granular base on the duodenal bulb (). EUS showed superficially spreading type hypoechoic lesion showing wall thickening of the second layer and partial indentation of the third layer of the duodenum (). Histological examination of the stomach was positive for H. pylori. Histology of the duodenal infiltration was compatible with MALT lymphoma: presence of lymphoepithelial lesions with a monoclonal population and positivity for CD20 and bcl-2 and negativity for CD3 and cyclin D1 (). An abdominal computed tomography (CT) scan demonstrated no lymph node enlargement. The patient was diagnosed as having stage IE1 MALT lymphoma according to the Ann Arbor classification modified by Musshoff. We decided to eradicate H. pylori with amoxicillin (1,000 mg twice daily), pantoprazol (40 mg twice daily), and clarithromycin (500 mg twice daily) for 2 weeks. At 2 months after the completion of the antibiotic treatment, right upper quadrant pain was subsided and there was no evidence of H. pylori in the gastric mucosa, but endoscopy disclosed no sign of regression of the duodenal lesion. Repeated endoscopy showed regression of the depressed lesion with granular base after 4 months (). EUS also demonstrated remission of wall thickening 7 months later (). Histological evaluation noted no lymphoepithelial lesion and immunoglobulin heavy chain rearrangement, but aggregates of lymphoid cells were persistent. Follow-up abdominal CT scans showed no evidence of lymph node enlargement. The patient was amenable to frequent endoscopies, so we decided to monitor the patient with short-term follow-up endoscopies and biopsies. The most recent endoscopy, 10 months after H. pylori eradication, showed grossly normal mucosa in the duodenal bulb.