Fig. 3

The pathological findings from the duplications. a The type 1b and type 2a duplications. Almost all the duplications include gastric mucosa. The duplication is on the dissected submucosal layer. b The macroscopic (left) and microscopic (right) findings of the anal side of the duplication. The duplication connects to the adjacent intestine via two orifices (asterisks). An ulcer is located in the center of the orifices (arrow). Most of the duplication contains gastric mucosa (black triangle) while the adjacent intestine has normal mucosa (white triangle). c The ruptured arterial vessel in the ulcer (high-power field). The ruptured vessel opens to the lumen of the intestine with fibrin clots (left, hematoxylin–eosin staining). Elastic Van Gieson staining showing that the ruptured vessel contains elastic fibers as an arterial vessel (right)