CASE REPORT Gut and Liver, Vol. 6, No. 2, April 2012, pp. 270-274 Regression of Advanced Gastric MALT Lymphoma after the Eradication of Helicobacter pylori Soo-Kyung Park, Hwoon-Yong Jung, Do Hoon Kim, Mi-Young Kim, Jeong Hoon Lee, Kwi Sook Choi, Kee Don Choi, Ho June Song, Gin Hyug Lee, and Ho Kim Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea A 66-year-old female presented with a 1-month history of dyspepsia. An initial upper gastrointestinal endoscopy with biopsy revealed a low-grade mucosa-associated lymphoid tissue (MALT) lymphoma. A rapid urease test was positive for Helicobacter pylori. Endoscopic ultrasound (EUS) and com- puted tomography (CT) revealed a 30×15-mm lymph node (LN) in the subcarinal area. Histopathologic and phenotypic analyses of the biopsy specimens obtained by EUS-guided ﬁne-needle aspiration revealed a MALT lymphoma, and the patient was diagnosed with a stage 4E gastric MALT lym- phoma. One year after H. pylori eradication, the lesion had disappeared, as demonstrated by endoscopy with biopsy, CT, fusion whole-body positron emission tomography, and EUS. Here, we describe a patient with gastric MALT lymphoma that metastasized to the mediastinal LN and regressed following H. pylori eradication. (Gut Liver 2012;6:270-274) Key Words: Marginal zone B-cell lymphoma; Stomach INTRODUCTION The most common primary lymphoma of the gastrointestinal (GI) tract is mucosa-associated lymphoid tissue (MALT) lym- phoma.1 Although 90% of gastric MALT lymphomas are related to the presence of Helicobacter pylori,2 areas other than the GI tract may be affected. We describe here a patient with gastric MALT lymphoma that metastasized to the mediastinal lymph node (LN) and regressed following H. pylori eradication. CASE REPORT A 66-year-old female presented with a 1-month history of dyspepsia. An initial upper GI endoscopy showed a shallow ulcerative lesion in the gastric high body and a hyperemic le- sion in the low body (Fig. 1A). A rapid urease test was positive for H. pylori . Histologic sections of the high and low bodies showed patchy infiltration of small lymphocytes into the lamina propria and lymphoepithelial lesions; the lymphocytes were fo- cally aggressive toward the gland (Fig. 1B). Phenotypic analysis showed that the lesion was positive for CD20, but negative for CD3, CD5, CD10, and Bcl-6, and that its proliferation rate was <2%, as shown by MIB1 (Ki-67) antibody analysis. Based on these histopathological and phenotypic features, the patient was diagnosed with low-grade MALT lymphoma. Staging pro- cedures were performed. Endoscopic ultrasound (EUS) revealed hypoechoic disruption of the mucosal and submucosal layers; moreover, the fourth layer was preserved and there was no evidence of locoregional lymphadenopathy (u-T1smN0) (Fig. 1C). A computed tomography (CT) scan showed a huge LN, about 30×15 mm in size, in the subcarinal area (Fig. 1D). Fu- sion whole body positron emission tomography (PET) showed a hypermetabolic lesion, suggestive of a malignant lesion, on the subcarinal area. (Fig. 1E). Bone marrow biopsy findings were normal. EUS of the subcarinal lesion showed 32×12 mm LN. Histopathological and phenotypic analysis of a biopsy sample obtained by EUS-guided fine needle aspiration (Fig. 1F) showed that the lesion was a MALT lymphoma (Fig. 1G). The patient was diagnosed with a stage 4E gastric MALT lymphoma. For H. pylori eradication, the patient was treated with a 14-day course of amoxicillin 2,000 mg a day, clarithromycin 1,000 mg a day Correspondence to: Hwoon-Yong Jung Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea Tel: +82-2-3010-3180, Fax: +82-2-476-0824, E-mail: hwoonymd@gmail.com Received on July 31, 2010. Revised on September 28, 2010. Accepted on October 11, 2010. pISSN 1976-2283 eISSN 2005-1212 http://dx.doi.org/10.5009/gnl.2012.6.2.270 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.