Congenital interstitial cell of cajal hyperplasia with neuronal intestinal dysplasia.

Interstitial cells of Cajal (ICCs) are intestinal pacemaker cells that initiate peristalsis in the stomach and intestine, and are considered to be precursors of gastrointestinal stromal tumors (GISTs). We report a 2-year-old girl who suffered from scanty stool passage since birth. On barium enema, the distal colon was rigid with narrow lumen, whereas the proximal colon was dilated and atonic. She received right hemicolectomy and ileostomy. Histopathologically, there was continuous proliferation of spindle cells located between the layers of the muscularis propria throughout the right colon. These spindle cells were positive for c-kit and CD34 but negative for myogenic or neurogenic markers, indicating they are ICCs. No germline or somatic mutation of the juxtamembrane domain of c-kit gene was detected. In addition, the changes of the submucosal plexus fulfilled the histologic criteria of neuronal intestinal dysplasia type B. To our knowledge, this is the first reported case of congenital ICC hyperplasia. Further studies of ICC development may contribute to better understanding of the pathogenesis of this congenital malformation and the tumorigenesis of GIST.