The primary esophageal lymphoma is extremely rare, and shows various morphologic characteristics. Only a single case of mucosa-associated lymphoid tissue (MALT) type lymphoma confined to the esophagus has been reported in the literature. A 61-yr-old man was referred to our hospital for evaluation of an esophageal submucosal tumor (SMT) that had been detected incidentally by endoscopy. He had a history of pulmonary tuberculosis with long-term anti-tuberculosis medication 15 yr before, and also had a history of syphilis, which had been treated one year before. He had been taking a synthetic thyroid hormones for the past 10 months because of an autoimmune thyroiditis. Endoscopy showed a longitudinal round and tubular shaped smooth elevated lesion, which was covered with intact mucosa and located at the mid to distal esophagus, 31 cm to 39 cm from the incisor teeth. Endoscopic ultrasonography (EUS) showed a huge longitudinal growing intermediate- to hypo-echoic mass located in the submucosal layer with internal small, various sized honeycomb-like anechoic lesions suggesting germinal centers. Subsequently, he underwent a surgery, which confirmed the mass as a primary esophageal low-grade B-cell lymphoma of MALT type.