NF1 and gastrointestinal stromal tumor: Diffuse growth of interstitial cells of Cajal (ICCs) in the gastrointestinal tract, termed ICC hyperplasia, has been observed in patients with specific tumor syndromes, including NF1, the Carney triad, and familial gastrointestinal stromal tumor (GIST) syndromes caused by germline mutations of c-KIT and platelet-derived growth factor receptor alpha oncogenes [14].