Long-term Follow-up of Gastric Adenocarcinoma with Chief Cell Differentiation Using Upper Gastrointestinal Tract Endoscopy

During upper endoscopic screening, a 71-year-old asymptomatic woman was found to have a small, yellowish, superficial elevated lesion in the upper third of her stomach, without any signs of atrophic mucosa. The patient underwent endoscopic follow-up once a year for approximately five years; however, changes in the tumor were barely detectable. Endoscopic mucosal resection was performed, and a histological examination confirmed the diagnosis of gastric adenocarcinoma with chief cell differentiation (GA-CCD). GA-CCD is rare; therefore, its clinicopathological features remain unknown. This case suggests that only barely detectable endoscopic changes may be observed in GA-CCD during long-term follow-up.