What condition is marked by the replacement of the normal esophageal lining with metaplastic columnar cells?

Barrett's Esophagus is characterized by the replacement of the normal squamous epithelial lining of the esophagus with metaplastic columnar cells due to chronic injury, often as a result of gastroesophageal reflux disease (GERD). This condition is significant because it is considered a precursor to esophageal adenocarcinoma, as the abnormal cells lead to dysplasia and increased cancer risk over time. The diagnosis is typically confirmed through an upper endoscopy with biopsy, which reveals the distinctive columnar cells that replace normal squamous cells.

While GERD can lead to Barrett's Esophagus by causing the irritation and inflammation necessary for the metaplastic change, it is not the condition that describes the change in the esophageal lining itself. Esophageal adenocarcinoma is a malignant condition that can arise from Barrett's Esophagus but is a different entity altogether, involving cancerous cells. A hiatal hernia, although potentially related to reflux symptoms, does not specifically refer to the change in the lining of the esophagus. Thus, Barrett's Esophagus is the correct answer as it directly describes the metaplastic process in the esophageal lining.