Relationship between gastric mucosal atrophy by endoscopy and non-ampullary duodenal epithelial tumors

Figure 1 Endoscopic gastric mucosal atrophy according to the Kyoto classification of gastritis and effect of gastric acidity on the duodenum. Part 1 comprises the bulb. Part 2 comprises the region from the superior duodenal angle to the papilla. Part 3 comprises the region from the anal side of the papilla to the horizontal part. Type C (C-0 to C-3) comprises no or mild endoscopic gastric mucosal atrophy. Type O (O-1 to O-p) comprises severe endoscopic gastric mucosal atrophy. Type C comprises normal to high acidity in the stomach and part 1. Type O comprises low acidity. Dark orange areas indicate highly acidic environments. Purple areas indicate the growth of Brunner’s glands.