An obese 52-year-old woman presents to a free clinic. She reports a 10 years history of “heartburn” that she has been treating with an over-the-counter proton pump inhibitor that has offered partial relief. Endoscopy is performed with biopsy identifying a change in the normal squamous lining of the lower esophagus to columnar epithelium. What type of cellular reaction is present in this case?

Briefly describe what caused these changes

What can the patient expect if she is not treated?