Fig. 1

The tumor T stage depend on AJCC 7th/8th edition system and EUS image features for each tumor T stage. a Endoscopic image of the lesion showed an ulcer located in the posterior wall of the body with peripheral mucosal consolidation. EUS image showed disappearance of first hyperechoic layer, mild thickness and hypoechoic change of the second hypoechoic layer, and normal third hyperechoic layer (arrows). Surgical resection confirmed poorly-differentiated and partial signet-ring cell gastric cancer confined to submucosal layer; b Gastroscopy showed an ulcer located in the anterior wall of gastric angulus. EUS image of the lesion showed disappearance of the first three layers and companied by muscularis propria visible indistinctly (arrows). The surgical specimen confirmed poorly-differentiated gastric cancer confined to the submucosal layer; c Endoscopic image showed a neoplasm located in the anterior wall of the antrum. EUS image of the lesion showed disappearance of the first three layers and companied by muscularis propria obvious thickening (arrows). The surgical specimen confirmed tumor infiltrated to the muscularis propria layer; d Endoscopic image of the lesion showed a neoplasm located in the lesser curvature side of the antrum with dirty surface. EUS image showed a thick hypoechoic lesion spreading from the mucosal to muscularis propria layer with an intact serosa layer (arrows). The surgical specimen confirmed tumor infiltrated to the subserosa; e Endoscopic image showed a large ulcer located in the upper posterior wall of the gastric body. EUS image showed an obviously thick hypoechoic lesion that spread throughout the entire wall and invaded the serosa infiltration (arrows). The serosal layer was irregularities in the outer edge of the gastric wall. The surgical specimen confirmed lesion confined to the serosal layer