Esophageal diverticula
Also known as: esophageal diverticulum, diverticula of the esophagus
Esophageal diverticula are outpouchings of the esophageal wall. They are classified by location as pharyngoesophageal (Zenker), midesophageal (traction), or epiphrenic, and by whether they involve all layers of the wall.
An esophageal diverticulum is a pouch that protrudes outward from the esophageal lumen. A true diverticulum contains all layers of the esophageal wall, while a false (pulsion) diverticulum consists only of mucosa and submucosa herniating through a weak point in the muscular layer. The distinction matters because the two arise by different mechanisms.
Three locations define the classic types. Zenker diverticulum is a pharyngoesophageal pulsion diverticulum that herniates posteriorly through Killian triangle, an area of weakness between the thyropharyngeus and cricopharyngeus muscles of the inferior pharyngeal constrictor. It results from failure of the upper esophageal sphincter to relax properly, raising pharyngeal pressure during swallowing. Midesophageal (traction) diverticula are true diverticula pulled outward by scarring from adjacent mediastinal inflammation, classically old granulomatous lymph node disease. Epiphrenic diverticula sit just above the diaphragm and are pulsion diverticula associated with distal esophageal motility disorders such as achalasia.
Symptoms depend on size and site. A Zenker diverticulum characteristically produces dysphagia, halitosis, regurgitation of undigested food, and a risk of aspiration pneumonia; a neck mass or gurgling may be present. Traction diverticula are frequently asymptomatic and found incidentally. Barium swallow is the standard imaging study, and blind endoscopic instrumentation carries a perforation risk when a Zenker pouch is present.
Esophageal diverticula appear in the gastrointestinal pathology section of USMLE Step 1. High-yield points are the anatomic location of Killian triangle, the pulsion-versus-traction mechanism, which types are true versus false diverticula, and the classic presentation of halitosis with regurgitation of undigested food in Zenker diverticulum.
Key takeaways
- Esophageal diverticula are outpouchings of the esophageal wall classified by location and layers involved.
- True diverticula contain all wall layers; false (pulsion) diverticula contain only mucosa and submucosa.
- Zenker diverticulum herniates through Killian triangle above the cricopharyngeus muscle.
- Midesophageal traction diverticula are pulled outward by adjacent mediastinal scarring.
- Epiphrenic diverticula sit above the diaphragm and are linked to distal motility disorders such as achalasia.