Hypogenesis of intramural vascularity and perivascular plexuses of gallbladder in patients with congenital biliary dilatation.

Background: We hypothesized neuronal disorders of the biliary tract as the cause of congenital biliary dilation (CBD).

Methods: Gallbladders were removed from a total of 15 patients who were categorized into two study groups: a CBD group (eight patients) and in a control group (neuroblastoma, acute myelogenous leukemia, wandering gallbladder, Wilms' tumor, glycogen storage disease, familial amyloid polyneuropathy; seven patients). Whole-mount preparations of the gallbladders were made to immunostain the intramural nerves.

Results: The intramural vascularity in the gallbladders of the CBD group (5.5 +/- 1.9/cm(2)) was significantly lower than that in the control group (27.6 +/- 14.4/cm(2)). The rate of perivascular plexuses on the surface of intramural vessels was also significantly lower in the CBD group than in the controls (37.7 +/- 18.1 vs. 80.2 +/- 17.4%, respectively). The numbers of ganglion cells per visual field were 38.5 +/- 24.0 and 42.3 +/- 20.6, respectively, in the CBD and control groups; this difference was not statistically significant.

Conclusions: There may be a mechanism in CBD causing contractile failure and dilatation of the biliary tract as a result of decreased intramural blood flow that accompanies the diminished vascularity.