A 58-year-old man with a 12-year history of heartburn undergoes upper endoscopy for Barrett esophagus surveillance. The endoscopist identifies the structure marked **A** in the diagram—a salmon-pink to red-orange columnar mucosa extending 4 cm above the gastroesophageal junction, sharply demarcated from the normal pale squamous mucosa above. Biopsies confirm specialized intestinal metaplasia with goblet cells. Which of the following best describes the pathophysiologic basis of the appearance and histology of the structure marked **A**?
A. Congenital heterotopia of gastric mucosa in the distal esophagus with parietal cell hyperplasia
B. Chronic gastroesophageal reflux-induced replacement of stratified squamous epithelium by columnar epithelium with intestinal metaplasia and goblet cells
C. Stricture formation from repeated thermal injury leading to fibrosis and columnar epithelial replacement
D. Acute esophagitis with inflammatory infiltration causing edema and hyperemia of the normal squamous mucosa
Explanation
Why option 1 is correct
The structure marked A (salmon-pink columnar mucosa above the GE junction) is Barrett esophagus, defined by chronic GERD-induced replacement of the normal stratified squamous epithelium of the distal esophagus by specialized intestinal metaplasia containing goblet cells. This is the defining pathophysiology per the ACG Barrett Esophagus Guideline 2022 and is the principal known precursor of esophageal adenocarcinoma. The salmon-pink color reflects the vascular nature of the columnar epithelium, which is distinct from the pale pearly appearance of normal squamous mucosa.
Why each distractor is wrong
Option 2 (Acute esophagitis with inflammatory infiltration): While acute esophagitis may cause erythema and edema, it does not produce the characteristic salmon-pink columnar mucosa with intestinal metaplasia and goblet cells. Acute esophagitis is typically associated with linear erosions (as shown in structure C) and is reversible, whereas Barrett esophagus is a chronic metaplastic change.
Option 3 (Congenital heterotopia of gastric mucosa): Heterotopic gastric mucosa (Meckel diverticulum-type lesion) is a congenital anomaly, not acquired from chronic GERD. It does not present as a large segment of columnar mucosa extending from the GE junction, and it is not associated with the risk of adenocarcinoma progression seen in Barrett esophagus.
Option 4 (Stricture formation from thermal injury): Thermal injury and stricture formation do not explain the columnar epithelial replacement or the presence of goblet cells. This mechanism would result in fibrotic narrowing, not the metaplastic change characteristic of Barrett esophagus.
