1. Figure 1a (a) Drawing illustrates the revised TNM staging system for esophageal cancer (seventh edition). (b) Endoscopic US image shows the normal esophageal wall, with five alternating hyper- and hypoechoic layers (arrowheads). The hyperechoic layer between the hypoechoic inner and outer muscularis propria (*) is the inner muscular connective tissue layer and is sometimes seen prominently. (Courtesy of Cheol-Min Shin, MD, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.)