A 76-year-old male was scheduled for gastric endoscopic submucosal dissection (ESD) of early-stage gastric cancer. During the ESD procedure, hypoxemia caused by laryngeal edema occurred and ESD was discontinued. Emergency tracheal intubation was attempted but it was difficult due to the presence of a large epiglottic cyst. Using a McGRATH laryngoscope, tracheal intubation was managed successfully. He was treated with steroids for laryngeal edema, and was discharged to home without any sequelae. An epiglottic cyst is a risk factor for difficult intubation. In patients who are scheduled for upper endoscopic treatment that requires sedation, a large epiglottic cyst should be removed before treatment.
