A 54-year-old man was referred to our hospital with an esophageal lesion. On esophagogastroduodenoscopy a pedunculated elevated lesion about 15mm in diameter was identified in the abdominal esophagus. The surface of the lesion had irregular nodules with white coating. We found no Barrett's mucosa around the lesion. A biopsy specimen of this tumor showed well-differentiated adenocarcinoma. A lower esophagus-proximal gastrectomy was performed because this tumor was suspected to invade the submucosal layer. Eventually, the histological diagnosis after resection was esophageal adenocarcinoma arising from cardiac glands, limited to the mucosal layer (M2). This origin of the esophageal adenocarcinoma is rare. Furthermore, this form of the tumor is especially unusual, and there have been few reports of similar cases.