A 65-yeаr оld mаn with а histоry оf smoking and chronic acid reflex seeks medical attention where he presents with dysphagia, weight loss and vomiting. As his attending physician, you perform an endoscopsy and collect biopsies along the length of his esophagus. Histologic examination of the biopsied materials reveals presence of a moderately differentiated mucin-producing glandular lesion that contains pleomorphic cells and originates from the distal third of the patient's esophagus. The number of infiltrating tissue leukocytes is normal. Which of the following conditions is he most likely to have?