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Enteric duplications and mesenteric, omental, and retroperitoneal
cysts are rare congenital anomalies. Most are recognized by the
age of 2 years. Enteric duplications can occur anywhere in the gastrointestinal
tract. Duplications and cysts can present in various fashions from
being asymptomatic and an incidental finding causing obstruction,
bleeding, or inflammation. Surgery is indicated in all instances
to prevent or treat these complications. The surgical management can
vary significantly depending on the location as well as the degree
of involvement of adjacent structure, in particular the intestine.
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Enteric duplications occur sporadically without any apparent
genetic predisposition. The reported incidence of enteric duplications
is 0.02%.1 Enteric duplications are commonly
associated with vertebral anomalies such as bifid, fused, or missing
vertebrae.2 When associated with vertebral anomalies,
enteric duplications may communicate with the spinal canal and are
termed neuroenteric cysts. Thoracic duplications
are more common in the presence of esophageal anomalies, and duplications of
the small intestine are commonly identified in association with
jejunoileal atresia. Colonic duplications are frequently associated
with genitourinary anomalies.3 Multiple duplications
are present in 10% to 20% of cases.
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Enteric duplications are defined by the following three characteristics: (1)
the presence of smooth muscle coat, (2) an intimate association
with the alimentary tract (often sharing a common wall), and (3)
an inner lining of intestinal epithelium. The incidence of enteric
duplications by anatomic location is shown in Table
401-1. While a duplication may be identified
anywhere from the mouth to the anus, the most common location is
in the distal ileum. Duplications can by cystic or tubular (eFig. 401.1). Some traverse
the diaphragm from the chest into the abdomen. Ectopic mucosa, most
commonly gastric, is identified in up to a third of duplication
cysts. Less commonly, the duplication may communicate with adjacent
bowel.4 The abnormal embryogenesis that leads to
an intestinal duplication is controversial. Because of the frequent
association with the spinal canal the split notochord syndrome was
proposed to explain neuroenteric cysts (eFig.
401.2). Others
have postulated duplications arise as a consequence of failed regression
of embryonic diverticula or aberrant recanalization of the solid stage. Environmental
stressors such as hypoxia, trauma, and vascular insufficiency have
all been proposed as causative factors. Lastly, the development
of colorectal duplications in association with urogenital duplications
has been attributed to partial or abortive twinning.4
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