The visualized portions of the small bowel are within normal limits. The stomach extends from the hemidiaphragms down to the true pelvis. This is an unusual, adolescent presentation of duodenal web. At surgery, there was marked hyperplasia and hypertrophy of the muscular layers of the duodenal bulb and stomach, due to chronic outlet obstruction. Patients with Down's syndrome are at increased risk for the spectrum of duodenal atresia and stenosis.
Duodenal web is a variant of duodenal stenosis with a congenital duodenal membrane.
Radiographically, a duodenal web is difficult to distinguish from stenosis. Duodenal atresia is much more common than duodenal stenosis and is considered to be a failure of recannulization which occurs at approximately 10 weeks gestation. An annular pancreas could also account for the duodenal obstruction which occurs with increased frequency in Down's syndrome, but was not seen in this case.