Duodenal mucosa-associated lymphoid tissue lymphomas: two cases and the evaluation of endoscopic ultrasonography.

Mucosa-associated lymphoid tissue lymphoma mainly arises in the stomach, with fewer than 30% arising in the small intestine. We describe here two cases of primary duodenal mucosa-associated lymphoid tissue lymphoma which were evaluated by endoscopic ultrasonography. A 52-year-old man underwent endoscopy due to abdominal pain, which demonstrated a depressed lesion on duodenal bulb. Endoscopic ultrasonographic finding was hypoechoic lesion invading the submucosa. The other case was a previously healthy 51-year-old man. Endoscopy showed a whitish granular lesion on duodenum third portion. Endoscopic ultrasonography image was similar to the first case, whereas abdominal computed tomography revealed enlargement of multiple lymph nodes. The first case was treated with eradication of Helicobacter pylori, after which the mucosal change and endoscopic ultrasound finding were normalized in 7 months. The second case was treated with cyclophosphamide, vincristine, prednisolone, and rituximab every 3 weeks. After 6 courses of chemotherapy, the patient achieved complete remission.