Background: Chronic idiopathic intestinal pseudoobstruction (CIIPO) is a rare syndrome with an obscure pathogenesis. The proto-oncogene c-kit encodes a transmembrane tyrosine kinase receptor C-KIT that is critical for the development of the interstitial cells of Cajal, cells that are regarded as being the pacemaker cells of the gut. Thus, C-KIT immunopositive (C-KIT-) cells in the muscle layers of the bowel are considered to be intestinal pacemaker cells.
Methods: In this study, the distribution of intestinal pacemaker cells was examined for the first time using C-KIT immunohistochemistry in an infant with CIIPO.
Results: C-KIT+ cells were found lying on either side of the border between the two muscle layers (longitudinal and circular) of the bowel and dispersed unevenly throughout both muscle layers. Myenteric plexuses were not demarcated by C-KIT+ cells. In contrast, in controls, C-KIT+ cells were located distinctly between the two muscle layers of the small bowel and dispersed evenly throughout the muscle layers of the colon. Myenteric plexuses were clearly demarcated by C-KIT+ cells.
Conclusions: This case demonstrates for the first time that there is abnormal distribution of intestinal pacemaker cells in CIIPO and provides new evidence that abnormal c-kit gene expression may be responsible for autonomic gut dysmotility. C-KIT immunohistochemistry may be an indispensable tool for diagnosing CIIPO.