Duplication of intestine is caused by failure of normal re-canalization of the gut during the embryonic period. The duplication may be cystic or tubular. The cystic duplications occur as cysts which are located on the gut wall (usually on the mesen-teric side). No communication between the cyst and intestinal lumen exists. The tubular duplications may occur as diverticula of variable length which communicate with the gut lumen, or the tubular duplications may take the form of parallel communicating tubes of variable length (ie, the single gut tube divides into two independent, parallel tubes which run separately for some distance and then unite to form a single gut tube once again).