The authors’ experience with 14 cases of the meconium plug syndrome and 13 cases of Hirschsprung’s disease is presented and the roentgenographic findings reviewed. Criteria for differentiation of meconium plug syndrome from Hirschsprung’s disease as well as from other pathologic processes, such as necrotizing enterocolitis of infancy and meconium ileus, are formulated and illustrated.

The following roentgen findings were almost always present in the meconium plug syndrome: small and large bowel distention, mottled or bulky intraluminal colonic masses reflecting excessive meconium retention and producing ribbon-like or sausage shaped defects on contrast enema roentgenograms. Air-fluid levels in the bowel were uncommon. Long contracted colonic segments simulating the transition segments of Hirschsprung’s disease, and due to collapse of the colon distal to the plug, may be seen involving the descending colon down to the sigmoid and/or rectum.

In distinction, excessive meconium was infrequently seen on plain film roentgenograms or contrast enema studies in 13 current cases of Hirschsprung’s disease in infants 4 days of age or younger. Additionally, air-fluid levels in the bowel were almost always present. If transition segments were identified in these young patients, they were localized to the rectosigmoid in most cases.

Hirschsprung’s disease remains, however, the most difficult problem in the differential diagnosis since it may occasionally present with clinical and roentgen findings almost identical with the meconium plug syndrome. Follow-up of all cases with the diagnosis of meconium plug syndrome is, therefore, recommended to exclude recurrence of symptoms in which event careful re-evaluation should be undertaken.