Upper gastrointestinal endoscopic submucosal dissection using an ultrathin endoscope: a retrospective, single-center evaluation.

Our results demonstrate that ESD with an ultrathin endoscope effectively reaches lesions in difficult locations and enables treatment within a small working space. Therefore, ESD using an ultrathin endoscope is a treatment option for lesions located distally to gastrointestinal stenosis, highly fibrotic lesions, and duodenal tumors.