This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Esophagus Applied Anatomy: GERD, Subject name: Pathology
A 54-year-old man with a long history of indigestion after meals and "heaburn" presents with upper abdominal pain. He was treated with proton-pump inhibitors for gastroesophageal reflux 3 years . An endoscopic biopsy of the lower esophagus shows glandular metaplasia. The patient described is at increased risk of developing which of the following diseases of the esophagus? 
Select and explain. 
A. Achalasia, B. Adenocarcinoma, C. Candidiasis, D. Plummer-Vinson syndrome
B: Adenocarcinoma
Answer: B: Adenocarcinoma 
Explanation: - Barrett esophagus carries a serious risk of malignant transformation to adenocarcinoma, risk correlates with length of involved esophagus & degree of dysplasia. - Viually all esophageal adenocarcinomas arise in the background of metaplastic epithelium of Barrett esophagus. - Symptoms & clinical course of adenocarcinoma of esophagus are similar to squamous cell carcinoma which include dysphagia, pain, occasionally bleeding.