Duodenal mucosa-associated lymphoid tissue lymphoma successfully treated by radiation therapy

Duodenal mucosa-associated lymphoid tissue (MALT) lymphoma is very rare, and little is known about its clinical characteristics, endoscopic and endosonographic features, and treatment. We hereby report a case of duodenal MALT lymphoma successfully treated by radiation therapy (RT). The patient was referred to us with epigastric pain and positive fecal occult blood testing. His symptoms failed to resolve with eradication therapy for a Helicobacter pylori infection that was diagnosed by a gastric biopsy performed elsewhere. Endoscopy at our institution revealed hypertrophy of the duodenal folds with erosions involving a third of the circumference few centimeters beyond the ampulla of Vater. Histopathologic and immunophenotypic features were consistent with a MALT lymphoma. There was no evidence of a H. pylori infection by gastric biopsy and urea breath test. Computed tomography scan of the abdomen and pelvis was normal. Endoscopic ultrasound showed thickening of the duodenal wall and hypoechoic infiltration into the submucosal layer. The patient was treated with RT with a complete response. Two and a half years later, he remains in complete clinical, endoscopic, and histopathologic remission. This case illustrates the importance of RT in patients with duodenal MALT lymphoma whose disease did not respond to H. pylori eradication.