Helicobacter pylori-Negative Differentiated Intramucosal Gastric Cancer in the Antrum With a Morphological Change in...

This case report presents two cases of differentiated intramucosal gastric cancer in the antrum. Both patients reported no history of Helicobacter pylori eradication therapy, and endoscopy and diagnostic tests indicated no H. pylori infection. Case 1 is a female patient in her 70s. Esophagoduodenogastroscopy (EGD) detected a depressed lesion. Adenocarcinoma was suspected; thus, endoscopic submucosal dissection (ESD) was performed to resect the lesion. The histological result was well-differentiated tubular adenocarcinoma, which predominantly demonstrated an intestinal mucin phenotype. The existence of a small elevated lesion in the same location was confirmed by reviewing the previous endoscopic record 52 months earlier. Case 2 is a male patient in his 60s in whom screening EGD detected an elevated lesion. The biopsy indicated gastric adenoma, and ESD was performed. The histological diagnosis was well-to-moderately differentiated tubular adenocarcinoma with a pure gastric phenotype. These results indicate that H. pylori-negative differentiated gastric carcinomas in the antrum occur as small elevated lesions that may gradually progress to a depressed form during a relatively long clinical course.