A woman in her 70s was an outpatient at our hospital. Esophagogastroduodenoscopy revealed a slightly elevated lesion with erosion, 10mm in diameter, located at the greater curvature of the antrum. Helicobacter pylori testing yielded negative results, and there was no atrophy of the gastric mucosa. Biopsy revealed a well-differentiated tubular adenocarcinoma. Complete en bloc resection was performed via endoscopic submucosal dissection, in accordance with the current Japanese guidelines. The gastric adenocarcinoma of the fundic gland type and coexisting with a hyperplastic or fundic gland polyp was negative according to the histological examination.