A 60-year-old man was successfully eradicated 5 years ago for Helicobacter pylori infection. In April 20XX, upper gastrointestinal endoscopy (EGD) showed mild gastric atrophy (C1) and a small erosion in the gastric antrum. In July of the same year, biopsy of the lesion was performed, and was diagnosed as signet-ring cell carcinoma. He was referred to our hospital, and the diagnosis of endoscopic work-up was early gastric cancer; 6 mm, 0-IIc, sig, cT1a, UL-. The 4-point biopsy was negative for cancer, and endoscopic submucosal dissection (ESD) was performed. The pathological result was noncurative resection; adenocarcinoma (por2> sig), pT1b2 (900 μm), pUL0, Ly0, V0, pHM0, pVM1. Thus, distal gastrectomy was additionally done. The postoperative pathological result was scirrhous gastric cancer with extensive cancer invasion in the muscularis propria centering on the ESD scar. As shown in this case, we need to keep in mind that poorly differentiated adenocarcinoma can develop in the Helicobacter pylori-eradicated gastric mucosa with mild atrophy without intestinal metaplasia.
