This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Which of the following condition is associated with an increased risk of developing adenocarcinoma of esophagus? 
Select and explain. 
A. Barret's esophagus, B. Long standing achalasia, C. Corrosive structure, D. Alcohol abuse
A: Barret's esophagus
Answer: A: Barret's esophagus 
Explanation: The metaplasia of esophageal squamous epithelium to columnar epithelium (Barrett's esophagus) is a complication of severe reflux esophagitis, and is a risk factor for esophageal adenocarcinoma. Endoscopic biopsy is the gold standard for confirmation of Barrett's esophagus. The hallmark of Barret's esophagus is the presence of mucus secreting goblet cells. Ref: Schwaz's Principles of Surgery, 9th Edition, Chapter 25