An early gastric cancer concurrent with a hyperplastic polyp in a patient confirmed negative for Helicobacter pylori.

A 58-year-old man was suspected of having a gastric polyp based on an upper gastrointestinal series. Esophagogastroduodenoscopy showed a gastric polyp, approximately 7mm in diameter, located at the greater curvature of the upper gastric body. Helicobacter pylori testing yielded negative results, and there was no atrophy of the gastric mucosa. Biopsy revealed a well differentiated tubular adenocarcinoma (Group 5). Endoscopic submucosal biopsies were performed, and histopathology revealed a well differentiated tubular adenocarcinoma coexisting with a hyperplastic polyp. Complete en bloc resection was performed, in accordance with the current Japanese guidelines.