Clinical meaning
An esophageal stricture is a narrowing of the esophageal lumen caused by fibrotic scar tissue formation within the esophageal wall, resulting in progressive difficulty swallowing (dysphagia). The most common cause is chronic gastroesophageal reflux disease (GERD), which accounts for approximately 70-80% of benign esophageal strictures. In GERD, the lower esophageal sphincter (LES) fails to maintain adequate resting tone, allowing retrograde flow of gastric acid, pepsin, and bile salts into the distal esophagus. Under normal physiological conditions, the esophageal mucosa is lined by non-keratinized stratified squamous epithelium, which is not designed to withstand repeated exposure to the acidic gastric contents (pH 1.0-2.0). Chronic acid exposure damages the epithelial barrier through direct hydrogen ion penetration, activation of pepsin at low pH (which degrades epithelial proteins), and bile salt-mediated disruption of cell membrane integrity. The initial injury produces reflux esophagitis, characterized by superficial mucosal erosions, inflammation, and edema. When acid exposure is severe, prolonged, or repetitive over months to years, the inflammatory process extends deeper into the submucosa and muscularis propria. The tissue repair process involves activation of fibroblasts and myofibroblasts within the...