Endoscopic ultrasonography for staging of T1a and T1b esophageal squamous cell carcinoma

Figure 1 Images of patients with stage T1a or T1b early esophageal squamous carcinoma. A-C: Stage T1a early esophageal squamous carcinoma; A: The lesion visualized by endoscopy and chromoendoscopy with iodine staining; B: The lesion visualized by ultrasonography. The lesion appeared as a hypoechoic line in the first layer, and the outside edge of the second layer was smooth; these two layers represent the mucosa and muscularis mucosa, and thus, the lesion was limited to the mucosa. The third layer (hyperechoic), which represented the submucosa, was intact; C: The post-operative pathology revealed that the tumor had invaded the lamina propria; therefore, this case was confirmed as T1a stage; D-F: Stage T1b early esophageal squamous carcinoma; D: The lesion visualized by endoscopy and chromoendoscopy with iodine staining; E: The lesion visualized by ultrasonography appeared as a hypoechoic line not only in the first and second layers but also in the third layer (hyperechoic), which represents the submucosa; the fourth layer (hypoechoic), which represents the muscularis propria, was intact; F: The postoperative pathology confirmed that the lesion covered the mucosa and had invaded into the submucosa; therefore, the patient was staged as T1b.