Endoscopic Submucosal Dissection of an Inverted Early Gastric Cancer-Forming False Gastric Diverticulum

Endoscopic submucosal dissection (ESD) is a standard treatment for early gastric cancer (EGC) that does not have any risk of lymph node or distant metastases. Here, we report a case of EGC resembling a diverticulum. Diverticular formation makes it difficult for endoscopists to determine the depth of invasion and to subsequently perform ESD. Because the false diverticulum does not have a muscular layer, this lesion can be treated with ESD. Our case was successfully treated with ESD. After ESD, the EGC was confined to the submucosal layer without vertical and lateral margin involvement. This is the first case in which ESD was successfully performed for a case of EGC that coexisted with a false gastric diverticulum. An additional, larger study is needed to determine the efficacy of ESD in various types of EGC, such as a false gastric diverticulum.