Duplications of the alimentary tract: clues to the missing links.

This is a review of the past 10 years' experience with duplications of the alimentary tract at the All India Institute of Medical Sciences, New Delhi, during which 14 infants and children with a total of 15 duplications were treated. Esophageal duplications represented the majority of cases (55%). Certain unexplained associations in this malformation led the authors to perform (1) detailed histological studies of the duplication cysts to seek explanation for the high incidence of gastric mucosa in their walls and its presence in duplications even in the distal parts of the gut, and (2) myelography and postmyelography computerized axial tomography scans to substantiate the spinal pathology. Three of four myelograms in patients with esophageal duplications showed an intraspinal pathology, and all three had vertebral defects. Histological evaluation of the cyst wall showed that gastric mucosa was the most common ectopic tissue in the walls of the cysts, and the tissues were in various primitive stages of differentiation. On the basis of these data, the authors hypothesize that (1) the embryonic endoderm of the entire alimentary tract has the potential to develop into gastric mucosa at the time of inception of duplications, which explains the high incidence of gastric mucosa and its presence in duplications even in the distal parts of the gut, (2) persistence of the embryonic relationship of the esophagus with the vertebral column is responsible for the high incidence of vertebral defects in esophageal duplications. The results of myelography in this series also support the theory of split notochord syndrome.