What types of early gastric cancer are indicated for endoscopic ultrasonography staging of invasion depth?

Figure 1 Case diagnosed correctly by endoscopic ultrasonography but misdiagnosed by endoscopy. A: Chromoendoscopy shows an irregular surface in a depressed lesion diagnosed as SM2; B: On this EUS image, irregular narrowing of sonographic layer 3 was not observed, and thus this lesion was considered an M/SM1 lesion; C: The histology by endoscopic submucosal dissection showed a differentiated-type intramucosal cancer with slightly fibrosis by biopsy; D: Histologic specimen of the lesion shows well differentiated-type adenocarcinoma limited to the mucosae (× 200). EUS: Endoscopic ultrasonography.

Figure 2 Case diagnosed correctly by endoscopic ultrasonography but misdiagnosed by endoscopy. A: Chromoendoscopy shows a reddish and smooth surface in a shallow depressed lesion diagnosed as M/SM1 (arrows). Histologically, the biopsy sample indicated a moderately to poorly differentiated adenocarcinoma; B: EUS image showing that a hypoechoic mass invaded the submucosal layer (sonographic layer 3). This lesion was diagnosed as SM2; C: Histology revealed that undifferentiated type adenocarcinoma massively invaded the submucosal layer (arrowheads); D: Moderately to poorly differentiated adenocarcinoma cells were observed in the gastric mucosae (× 200). EUS: Endoscopic ultrasonography.

Figure 3 Flowchart of endoscopic ultrasonography diagnostic strategy for early gastric cancer. EUS should be considered performing the following lesions: (1) differentiated-type cancers without UL diagnosed as invading to SM2; and (2) undifferentiated-type cancers diagnosed by conventional endoscopy as meeting the expanded-indication criteria for endoscopic resection. In cases rather than those lesions, however, EUS may not be needed for the preoperative determination of the depth of EGCs. SM2 indicates invasion ≥ 500 μm into the submucosal layer. EGC: Early gastric cancer; EUS: Endoscopic ultrasonography.