GERD and Peptic Ulcer Disease USMLE Step 1 Practice Question
A 56-year-old man with a 15-year history of chronic heartburn presents to the gastroenterology clinic for evaluation of persistent retrosternal discomfort not fully controlled by omeprazole. He reports frequent nocturnal reflux symptoms. Vital signs are stable and physical examination is unremarkable. Upper endoscopy reveals a demarcated area of salmon-pink mucosa extending 6 cm proximal to the gastroesophageal junction, distinct from the surrounding pale squamous epithelium. Multiple biopsies from this region show nonciliated columnar epithelium with abundant goblet cells interspersed among mucus-secreting cells. Which of the following mechanisms best explains the histologic findings in this patient?
Answer choices
- AChronic exposure of the distal esophagus to acidic gastric refluxate causing squamous epithelium to undergo metaplasia to columnar epitheliumCorrect answer
- BDysplastic transformation of normal esophageal mucosa secondary to repeated mechanical trauma from food passage
- CProliferation of ectopic gastric mucosa that was present since embryologic development
- DIntestinal infection with Helicobacter pylori extending proximally from the stomach into the esophagus
- EAllergic inflammation of the esophageal mucosa leading to epithelial hyperplasia and cellular reorganization
- FImpaired esophageal peristalsis causing chronic stasis of gastric contents in the distal esophagus
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