Fig. 2 Endoscopic submucosal dissection (ESD) procedure. a The resection borders were marked. b A solution of indigo carmine and glycerol was injected to lift the submucosa. The mucosa was cut around the lesion. c A clip with dental floss provided traction. d The lesion was quickly peeled away using an insulation-tipped knife. e The tumor was resected en bloc. f The tumor was divided into smaller pieces and retrieved from the esophagus using a snare. g Endoscopic images after ESD showed a flat ulcer. h, I No residual tumor or stenosis was observed endoscopically at 4 months after treatment.