Abstract
A de novo whitish subepithelial lesion (SEL) with irregular vascular hyperplasia was detected in the lower thoracic esophagus during endoscopic surveillance. Special types of esophageal cancer were suspected; however, endoscopic biopsy specimens were inadequate for a diagnosis. Ten days later, endoscopic ultrasound showed a 7-mm homogeneously hypoechoic round mass in the submucosa, and a biopsy confirmed a histological diagnosis of esophageal neuroendocrine carcinoma (eNEC). Based on the clinical diagnosis of cT2N0M0, subtotal esophagectomy followed by adjuvant chemotherapy was performed immediately after endoscopic reexamination revealing a 20-mm reddish SEL. We herein report the marked changes in endoscopic findings of eNEC within 1.5 months.