An esophageal duplication mass or cyst is a rare inherited condition in which a mass of cells forms alongside the esophagus (the tube that connects the mouth to the stomach) during fetal development. It usually runs along the esophagus or, even more rarely, it is attached to it.
This condition is usually diagnosed in early childhood. Symptoms usually appear when the mass presses against the lungs or the esophagus and would include respiratory difficulties, trouble swallowing, and vomiting. Smaller cysts may never cause symptoms and may only be found incidentally.
Surgical or endoscopic removal is the common treatment.