Our patient was a 59-year-old Taiwanese, well-nourished man with a history of hypertension for 4 years and hyperthyroidism for one more year that were well controlled. He was a heavy smoker (1–2 packs per day) for 30 years, and had only quit for a few months. He had received a lumbar laminectomy to treat spinal stenosis 6 years previously. He had no relevant family history. He had developed thyrotoxic exophthalmos 2–3 months prior to presentation and received steroid pulse therapy for compressive optic neuropathy. The symptoms were relieved for 2–3 months after the steroid therapy. He visited our clinic after a positive fecal occult blood test (132 ng/mL) but reported no change to his bowel habits. A physical examination revealed bilateral eyes proptosis and mild obesity. Complete colonoscopy revealed one flat polyp, 0.3 cm in size, located 35 cm from his anal verge, and another polypoid polyp with a wide base, 2.0 cm in size with a slightly irregular border, located 25 cm from his anal verge. The smaller polyp was removed by polypectomy. We biopsied the larger polyp because of its wide base. A pathological examination of the specimen revealed it was a hyperplastic polyp. We did not perform an endoscopic ultrasound because we intended to directly remove the polyp. The polyp was then removed by endoscopic mucosal resection followed by clipping. There were no unexpected events after the procedure. A pathological examination of the removed polyps identified the smaller polyp as adenomatous and the larger one as a MALT lymphoma, with a polypoid colonic mucosa and atypical lymphoid cells infiltrating the lamina propria. An immunohistochemical study demonstrated that the larger polyp was positive for CD20, CD5, and Bcl-2, and negative for CD10 and cyclin D1. These results supported our diagnosis of extranodal marginal zone lymphoma of MALT type. However, when reviewed by a pathologist, the margins of the endoscopic mucosal resection specimen were found to be positive (cauterized margin with lymphoma cells; Fig. ), although it was free on gross examination. Our patient was transferred to the hematologist’s clinic, and further studies revealed no disease dissemination. A physical examination revealed no palpable lymph nodes, no petechiae, and no hepatosplenomegaly. A computed tomography scan revealed no metastatic tumors, nor enlarged lymph nodes. A bone marrow biopsy of his right iliac bone revealed small aggregates of small lymphoid cells but an immunohistochemical study did not suggest any MALT lymphoma involvement. An otorhinolaryngologist found no abnormalities in his ear drums, nose, oral cavity, nasopharynx, or vocal cord. The tumor stage was E-I according to the Ann Arbor staging system modified by Musshoff []. Our patient had regular follow-up appointments with the hematologist and proctologist without any signs of lymphoma recurrence for 3 years. Two years after his initial presentation, a colonoscopy revealed a transverse colon adenoma and a rectal hyperplastic polyp. The previous site of the MALT lymphoma was free of tumor, and no other evidence of MALT lymphomas was found. A polypectomy was performed with no unexpected events. According to his history and throughout his clinical course, our patient had no symptoms or signs of a peptic ulcer. We did not perform a panendoscopy nor test for Helicobacter pylori. There were no other symptoms or signs compatible with autoimmune diseases or viral infection. We did not test for Epstein-Barr virus (EBV). During the last 2 years, he has had no epigastralgia, no acid reflux, and no tarry stool.