Endoscopic Submucosal Dissection of a Gastric Cardia Cancer Demonstrating Distinctive Progression from a Small Hyperplastic Polyp

We report a rare case of endoscopic observations of the distinctive progression of a small hyperplastic polyp (HP) with low grade dysplasia to early gastric cardia cancer in a background of atrophic pangastritis that led to an uninhabitable state for Helicobacter pylori, over the course of thirty months with no obvious superficial morphological changes, and it was removed en bloc by endoscopic submucosal dissection using the insulation-tipped diathermic knife-2. The resected lesion was histologically diagnosed as well-differentiated adenocarcinoma mostly with some moderate-differentiated adenocarcinoma extending 400 μm into the submucosal layer without vessel infiltrations, in which hyperplastic components were not detected. There were features of both the background atrophic pangastritis that led to an uninhabitable state for Helicobacter pylori and cardia location, which may be a part of the various processes underlying the distinctive progression. One growth process of gastric cardia cancers was clarified in our case. Therefore, if atypical cells are observed even in small HPs, particularly with features as observed in our case, endoscopic resection should be considered prophylactically regardless of the presence of gross morphological changes, while performing yearly surveillance.