Early-stage Neuroendocrine Carcinoma of the Esophagus Observed with Annual Endoscopy for Three Years

An 80-year-old man was found to have a reddish depressed lesion on the middle thoracic esophagus. The morphology of the lesion had been almost unchanged for 3 years, but it transformed to a 2-cm depressed lesion with elevated margins and an irregular nodular surface. The lesion was resected endoscopically and ultimately diagnosed as a combined neuroendocrine carcinoma and squamous cell carcinoma with submucosal invasion. The patient was additionally treated with chemoradiotherapy but died of the primary disease eight months after the initial treatment. It is important to elucidate the natural history of this disease at an early stage.