Congenital interstitial cell of Cajal hyperplasia with neuronal intestinaldysplasia

Interstitial cells of Cajal (ICCs) an intestinal pacemaker cells that initi ate peristalsis in the stomach and intestine, and are considered to be prec ursors of gastrointestinal stromal tumors (GISTs). We report a 2-year-old g irl who suffered from scanty stool passage since birth. On barium enema, th e distal colon was rigid with narrow lumen, whereas the proximal colon was dilated and atonic. She received right hemicolectomy and ileostomy. Histopa thologically there was continuous proliferation of spindle cells located be tween the layers of the muscularis propria throughout the right colon. Thes e spindle cells were positive for c-kit and CD34 bur negative for myogenic or neurogenic markers. indicating they are ICCs. No germline or somatic mut ation of the juxtamembrane domain of c-kit gene was detected. In addition;t he changes of the submucosal plexus fulfilled the histologic criteria of ne uronal intestinal dysplasia type B. To our knowledge, this is the first rep orted case of congenital ICC hyperplasia. Further studies of ICC developmen t may contribute to better understanding of the pathogenesis of this congen ital malformation and the tumorigenesis of GIST.