Cystic duplications are partially intramural or attached to the wall, and often share the muscularis propria. All layers of the GI tract are present.

The epithelial lining is a simple columnar one, with foveolar type mucin. These cysts can be lined by any type of epithelium from the tubular gut or respiratory tract.

Most GI duplications occur in the jejunoileal and esophageal portions, while those in the stomach account for <10%. Duplications are continguous developmental abnormalities consisting of cystic or tubular replicas of the GI tract.