Article ID: 24022
The case involved a man in his 50s. Upper gastrointestinal endoscopy (EGD) at screening revealed an elevated lesion on the anterior wall of the gastric fornix. It was flagged for follow-up, and screening EGD was performed 1 year later. There was no obvious increase in the elevated lesion, but there were irregular findings of redness with slight ridges at the margins. A biopsy was performed and it was considered a gastric tumor. At precise EGD, he was diagnosed with gastric cancer that remained in the mucous membrane, for which he underwent endoscopic submucosal dissection (ESD). From the results of various tests, it was considered that the background gastric mucosa was not infected with Helicobacter pylori. In the ESD samples, cells histopathologically resembling main cells and parietal cells proliferated with irregular branching structures, and invasion into the deep submucosal layer (SM2) was observed. Immunostaining showed that tumor cells were positive for MUC6, pepsinogen I, H+/K+-ATPase, and MUC5AC, and differentiated into the foveolar epithelium as well as main and parietal cells. Based on these results, he was diagnosed with gastric adenocarcinoma of the fundic gland mucosa. Follow-up gastrectomy was performed due to submucosal invasion (SM2) and positive vertical stump, but no residual tumor or lymph node metastasis was observed. We report that we have encountered one case of gastric fundus mucosal adenocarcinoma against the background of pylori uninfection, which could be diagnosed based on screening EGD.
