Zenker diverticulum is classified as what type of diverticulum?

Zenker diverticulum is classified as a false diverticulum. This classification is based on its anatomical structure; a false diverticulum does not include all layers of the bowel wall in its formation. Specifically, Zenker diverticulum forms due to a weakness in the muscle layer of the esophagus, leading to a protrusion of the mucosa through the muscular wall.

In contrast, true diverticula involve the entire wall of the organ, including all layers—mucosa, submucosa, and muscularis. Since Zenker diverticulum occurs as an outpouching of only the mucosal layer due to esophageal motility issues, it falls into the category of false diverticula. This understanding is essential in pathology, as it helps in distinguishing the various diverticular conditions based on their structure and implications for treatment.