A 52 year old man presented with dysphagia diagnosed of having adenocarcinoma of esophagus. It mostly seen in:

Barrett esophagus secondary to long-standing reflux disease is the single most impoant risk factor for adenocarcinoma. Patients with Barrett esophagus are 30 to 125 times more likely to have adenocarcinoma of the esophagus than the general population. Microscopically, adenocarcinoma almost always originates in metaplastic Barrett's mucosa, and resembles gastric cancer. Ref: Jobe B.A., Hunter J.G., Peters J.H. (2010). Chapter 25. Esophagus and Diaphragmatic Hernia. In F.C. Brunicardi, D.K. Andersen, T.R. Billiar, D.L. Dunn, J.G. Hunter, J.B. Matthews, R.E. Pollock (Eds), Schwaz's Principles of Surgery, 9e.