Immaturity of the myenteric plexus is the aetiology of meconium ileus without mucoviscidosis: a histopathologic study.

The most common aetiology of meconium ileus is a deficiency in trypsin activity caused by cystic fibrosis. The pathogenesis of meconium ileus without mucoviscidosis is less well understood, although a number of causative factors have been suggested. The symptoms and clinical course of nine patients with meconium ileus without mucoviscidosis were reviewed, and the myenteric plexus of a surgical specimen of intestine was examined histologically and cytometrically. The nuclei of the intramural ganglion cells were much smaller than were seen in normal newborn infants. The nuclear areas resembled those seen in fetuses of 5-6 months gestational age, but the number of ganglion cells approached normal. This immaturity of the ganglia was observed both in the contracted distal ileum and dilated proximal ileum. Patients with an ileostomy passed solid faeces for about 1 to 2 months postoperatively, after which time the faeces became watery. The intramural ganglia were mature at the time of ileostomy closure. We conclude that immaturity of the myenteric plexus in the ileum and colon seems to be the main aetiologic factor in meconium ileus without mucoviscidosis.