A case of advanced gastric cancer diagnosed during regular surveillance after endoscopic submucosal dissection

Despite extensive research on early gastric cancer after Helicobacter pylori eradication, knowledge regarding advanced-stage gastric cancer remains limited. We report a case of advanced gastric cancer demonstrating progression during annual surveillance after endoscopic submucosal dissection. A 77-year-old man had a small, reddish lesion in the upper gastric body that gradually enlarged over several years. Repeated biopsies showed no evidence of malignancy until five years later when the lesion developed a submucosal tumor-like elevation with ulceration. Histological examination confirmed adenocarcinoma with malignant ascites, leading to a diagnosis of stage IVB gastric cancer. In conclusion, following H. pylori eradication, gastric cancer may present as a submucosal tumor-like elevation, and its diagnosis using standard forceps biopsies may be difficult.