Significance of interstitial cells of Cajal in Hirschsprung's disease and intestinal neuronal dysplasia - A comparative study.

BACKGROUND

The normal motility of the gastrointestinal tract depends on the enteric nervous system, the smooth muscle, and the interstitial cells of Cajal (ICC). Hirschsprung's disease (HD) is the most common motility disorder in the pediatric age group, which needs to be differentiated from other motility disorders, especially intestinal neuronal dysplasia- type B (IND-B). The aim of this study is to analyze the distribution of ICCs in HD and IND-B with reference to location and density as well as to evaluate the importance of submucosal nerve trunk thickness in differentiating HD from IND-B.

MATERIALS AND

METHODS

The distribution and number of ICCs were assessed by immunohistochemistry. ICCs were evaluated in the inner circular layer, outer longitudinal layer, and the myenteric plexus. The presence of hyperganglionosis, giant ganglia, and ectopic ganglia was assessed in IND-B and compared to the controls. Immunohistochemistry was performed for CD 117 (c-kit) and Anoctamin-1 (Ano-1) to identify the ICCs, along with synaptophysin and S-100 for identification of the ganglion cells and nerve bundles, respectively. The submucosal nerve trunk thickness was evaluated by nerve trunk morphometry in all three groups.

RESULTS

ICCs were significantly reduced in all three layers in IND-B and HD as compared to the normal controls ( P value < 0.5). The cases of IND-B showed a significant reduction of ICCs in the inner circular and outer longitudinal layers as compared to HD, while the number of ICCs in the myenteric plexus was similar in these groups. The nerve trunk thickness was found to be significantly higher in HD and IND-B compared to the normal controls with IND-B showing even higher submucosal nerve trunk thickness than HD.

CONCLUSION

Our findings suggest that there is a significant difference in the distribution of ICCs in the two muscular layers of HD and IND-B. Further multicenter studies are required to evaluate the utility of ICCs as a potential marker for differentiating HD from IND-B. Although nerve trunk thickness greater than 40 μ can be useful in differentiating HD from other non-motility disorders, it cannot be used to distinguish HD from IND-B.