USMLE Step 1 Question 351

Question:

A 45-year-old man cannot leave home without antacids because he has had severe heartburn with every meal for 10 years. Which of the following is likely to be seen on biopsy of his lower esophagus?

Correct Answer: A.  Columnar metaplasia

Barrett’s esophagus is a complication of gastro-esophageal reflux disease (GERD). The lower 2/3 of the esophagus is composed of stratified squamous epithelium. With repeated exposure to caustic gastic acid, tissue in the lower esophagus is replaced with columnar glandular epithelium with goblet cells resembling glandular cells of the intestines that secrete mucin. This process is called metaplasia, in this case columnar.

Hyperplasia is an increase in the number of cells in a tissue region, such as endometrial hyperplasia. Hypertrophy describes enlargement of existing cells, such as in hypertrophic cardiomyopathy. Squamous metaplasia would not occur in the esophagus, where epithelium is normally squamous. Squamous metaplasia can occur in the bladder, cervix, or lungs.