2018 Volume 60 Issue 8 Pages 1450-1463
Helicobacter pylori（HP）-negative gastric cancers are divided into HP-uninfected, post-HP-infected-and-eradicated types. We describe HP-uninfected gastric cancers and post-HP-eradicated gastric cancers. Typically, HP-uninfected cancers are undifferentiated adenocarcinoma and gastric adenocarcinoma of the fundic gland type. Almost all undifferentiated adenocarcinomas are signet-ring cell carcinomas. Their characteristic findings are a pale lesion and Ⅱc or Ⅱb type. The endoscopic characteristics of gastric adenocarcinoma of fundic gland type are a submucosal tumor-like appearance originating from the fundic gland area. Other types of HP-uninfected cancers are hereditary diffuse gastric cancer, gastric cancer associated with familial polyposis, gastric cancer associated with autoimmune gastritis, and Epstein-Barr-virus-related gastric cancer. It is important to be aware of HP-uninfected gastric cancers in order to be able to detect gastric cancer.
Almost all post-HP-eradicated cancers are well-differentiated adenocarcinoma and the depressed type. Post-HP-eradicated gastric cancers are covered with normal foveolar epithelium and with epithelium with low-grade atypia （ELA） histologically.
Furthermore, it was reported that HP-negative gastric cancer developed a gastritis-like appearance. It was also reported that making a diagnosis by biopsy and making a diagnosis of the margin of the lesion are difficult.
