Congenital megacolon: diagnosis using size of sub-mucosal nerve trunk as a criteria

Cholinergic hyperinnervation in submucosa of aganglionic segment of Hirschsprung's disease has been described. However, objective measurement of the nerve fibers was insufficiently reported.

To study the amount and size of hypertrophic submucosal nerve trunks in the aganglionic segment of Hirschsprung's disease, semiquantitatively and evaluate the possibility of using the size as objective diagnostic criteria.

Thirteen specimens from aganglionic segments from Hirschsprung's disease and six specimens from the age-matched control subjected without colonic innervation disorders were studied with the S-100 immunohistochemical technic. The submucosal nerve trunks were counted per ten HPF and measured in width, semiquantitatively. Fiber sizes were stratified into small (<20 micrometers), medium (20-40 micrometers), and large (>40 micrometers). Maximum fiber size in each specimen was also recorded.

Average density of submucosal nerve trunk in the aganglionic segment and the control were 12.5 and 3.4 fibers per ten HPF, respectively. The large nerve trunks were detected in 12 of 13 aganglionic specimens and none was detected in the controls. The maximum fiber size in aganglionic segments was 78.2 micrometers, compared to 24.1 micrometers in the control group. The sensitivity and specificity to set the presence of hypertrophic nerve trunk, larger than 40 micrometers as a diagnostic criteria for Hirschsprung's disease were 92.3 and 100 per cent, respectively. The data suggest the use of this size as an objective diagnostic criterion, which may be valuable in rectal suction biopsy specimens.