Fig. 1

a Esophagogastroduodenoscopy shows an irregular, reddish, flat lesion in the posterior wall of the mid-esophagus. b Lugol’s iodine chromoendoscopy shows an unstained lesion that is located in the posterior wall of the mid-esophagus. c Narrow band imaging endoscopy shows a brownish area. d Magnifying endoscopy with narrow band imaging shows a microvascular pattern with irregular, fine, reticular blood vessels near the center of the lesion. e Endoscopic ultrasound image of the lesion limited to the mucosa. f En bloc resection by endoscopic submucosal dissection