This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart & Pericardium, Subject name: Surgery
[{'content': "A 40-year-old woman treated for many years for gastroesophageal reflux develops dysphagia and weight loss. Previous esophagoscopy has revealed cellular atypia. An esophagoscopy is about to be performed. What is it most likely to reveal? \nSelect and explain. \nA. Leiomyoma arising from the long esophageal muscular layer, B. Squamous cell carcinoma arising from esophageal mucosal lining, C. Adenocarcinoma originated from islands of Barrett's esophagus, D. Adenocarcinoma extending from the stomach", 'role': 'user'}, {'content': "Answer: C \nExplanation: Adenocarcinoma, originated from islands of Barrett's esophagus, is today the most common cancer of the esophagus in the United States.", 'role': 'assistant'}]