Innervation patterns in congenital biliary dilatation

The innervation of choledochal cysts was studied to see if the distribution of innervating ganglion cells can be utilized as a possible indicator of the damage and dilatation process of choledochus. Specimens from 32 patients aged 1 month to 12 years were stained by the immunoperoxidase method with neural tissue-specific antibodies, the innervating ganglion cells were counted and their number was correlated with the clinical severity, patient's age-at-surgery, and intraoperative cholangiographic and/or ERCP findings. In cystic dilatation, the total number of ganglion cells within the choledochal wall was significantly lower than in control specimens regardless of the diameter of the choledochal cyst, age-at-surgery, or clinical course. In fusiform dilatation, the total number of ganglion cells varied according to the severity of the clinical presentation, and the diameter of the fusiform choledochus increased in proportion to the patient's age-at-surgery. The distribution of innervating ganglion cells is thought to correlate quantitatively with the damage and dilatation process responsible for the choledochal cyst. These results may support a hypothesis that the pathogenesis of cystic dilatation proceeds antenatally or soon after birth, while that of fusiform dilatation begins after birth.