Differentiation of esophageal cancer of m3•sm1 from sm2•sm3 by EUS

It is mandatory to have a confident diagnosis for an extension of indication of endoscopic mucosal resection. From the standpoint of endoscopic ultrasonography (EUS) using a high-frequency ultrasound probe, it is important to scan as perpendicularly as possible in order to visualize the esophageal wall having at least nine layers. It is also important to confirm the deepest point of invasion by moving the probe over the whole area of the lesion of interest under endoscopic control. It is crucial to interpret subtle grayscale changes, visualized as a low-echoic areas. This is useful in order to be able to differentiate mass from cysts, esophageal glands, or blood vessels. It is especially necessary to recognize the lymph follicles, usually found in the lamina propria. in superficial esophageal carcinoma. A tip to use, when trying to differentiate m3.sm1 from sm2.sm3, is to focus on the existence of the 3/9 layer of the muscularis mucosae during a high-frequency-probe EUS.