Helicobacter pylori-Negative Advanced Gastric Cancer Arising from the Gastric Mucosa without Inflammation, Atrophy, or Intestinal Metaplasia

Gastric cancer is strongly associated with atrophic gastritis associated with Helicobacter pylori infection. The eradication of H. pylori has been reported to improve inflammation of the gastric mucosa, atrophy, and intestinal metaplasia and has also been shown to inhibit the development and growth of gastric cancer. Advanced gastric cancer from H. pylori-negative mucosa without inflammation, atrophy, or intestinal epithelialization is rarely found. We report on two cases of advanced gastric cancer without endoscopic evidence of gastric mucosal atrophy. One case was in the gastric angle 9 years after H. pylori eradication and the other case was in the pylorus of an uninfected stomach. Although gastric cancer is strongly associated with atrophic gastritis caused by H. pylori infection, postoperative histopathological examination of the stomach in both cases showed no inflammation, atrophy, or intestinal metaplasia. Poorly differentiated adenocarcinomas were confirmed at the microscopic level, and both cases were determined to be type 4 using the Borrmann classification. There is a body of evidence showing that H. pylori infection can cause gastric cancer and is the most prevalent infection-induced cancer in the world. The 2 cases here displayed different carcinogenesis than gastric mucosal atrophy caused by H. pylori infection. With the spread of H. pylori eradication treatments and an increasing number of uninfected patients, these case reports can contribute to future strategies for the diagnosis of gastric cancer.