After endoscopic treatment for esophageal cancer, a 65-year-old male underwent surveillance esophagogastroduodenoscopy. A 12-mm discolored flat lesion was noted on the greater curvature of the middle gastric body. Magnifying endoscopy with blue laser imaging demonstrated an irregular papillary surface. Biopsy revealed atypical cells with mucus and irregularly distributed nuclei. The lesion was diagnosed as a gastric-type neoplasm with low atypia. Thereafter, endoscopic submucosal dissection (ESD) was conducted and specimen was sent for biopsy. The ESD specimen suggested a signet-ring cell carcinoma with MUC5AC-positive phenotype and adenocarcinoma of the fundic gland type, with MUC6 positivity and pepsinogen I positivity in the shallow and deeper layers, respectively. Moreover, the cervical region of fundic glands demonstrated a transformation zone of the signet-ring cell carcinoma into an adenocarcinoma of the fundic gland type. Herein, we report this rare case along with a literature review.