Park SK, et al: Regression of Advanced Gastric MALT Lymphoma after the Eradication of Helicobacter pylori 271 Fig. 1. Initial diagnostic tests. (A) Initial upper gastrointestinal endoscopy displaying a shallow ulcerative lesion in the gastric high body and a hyperemic lesion in the gastric low body. (B) Histopathologic examination of a gastric biopsy specimen displaying patchy infiltration of small lymphocytes and lymphoepithelial lesions in the lamina propria, which suggest the existence of a mucosa-associated lymphoid tissue (MALT) lymphoma (H&E stain, ×400). (C) Endoscopic ultrasound (EUS) analysis displaying hypoechoic disruption of the mucosal and submucosal layers. (D) Computed tomography scan displaying a 30×15 mm lymph node (LN) in the subcarinal area. (E) Positron emission tomography analysis display- ing a hypermetabolic lesion suggestive of a malignant lesion in the subcarinal area. (F) EUS analysis of the subcarinal lesion revealing a 32×12 mm LN. (G) Histopathologic examination of LN tissue, with the patchy infiltration of small lymphocytes, suggesting a MALT lymphoma (H&E stain, ×400). and pantoprazole 80 mg a day. An endoscopy performed 2 months after treatment showed that the gastric high and low bodies were pale and flat, with no evidence of lymphoma infiltration (Fig. 2A and C). EUS of the subcarinal area and CT showed that the LN had decreased markedly in size, to 12×11 mm (Fig. 2E and G). Follow-up PET showed no significantly abnormal hypermetabolic lesions (Fig. 2I). One year after treatment, all assessments, including endos- copy with biopsy, CT, PET, and EUS, showed normal results (Fig. 2B, D, F, H and J). At present, 14 months later, the patient remains in complete remission. DISCUSSION More than 90% of gastric lymphomas are related to the pres- ence of H. pylori; hence, eradication of H. pylori is the favored initial treatment for patients with early-stage H. pylori-positive gastric MALT lymphoma.2 However, the association between extragastric MALT lym- phoma and H. pylori is not clear. Although several case reports have described the regression of extragastric MALT lymphomas after H. pylori eradication,3,4 one study showed that the majority of patients with extragastric MALT lymphoma did not benefit from H. pylori eradication.5 In addition, there have been a few case reports showing that H. pylori eradication has led to the regression of advanced gas- tric MALT lymphomas simultaneously involving two or more organs other than the stomach.6,7 Recirculation of H. pylori - specific T-cells from the stomach to other organs via the blood or lymphatic system may trigger an inflammatory response in other MALT-lymphoma containing organs.3,4,6,7 Alternatively, abnormal cells may spread from the stomach to other organs via the blood or lymphatic system.5,8 H. pylori eradication may also lead to the regression of sec- ondarily involved perigastric LN and bone marrow. However, our patient was different, in that H. pylori eradication led to the regression of a mediastinal LN.