Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the digestive tract, originating from interstitial cells of Cajal or their precursors and located in the stomach (60%) and the proximal end of the small intestine (30%).[1] They contain gain-of-function mutations in c-KIT (75%–80%) or platelet-derived growth factor receptor alpha (PDGFRA) genes (5%–10%).[2,3] In wild-type GISTs that lack c-KIT and PDGFRA mutations, loss-of-function mutations in the succinate dehydrogenase or loss of succinate dehydrogenase subunit B have been observed. The gene discussed is KIT; the disease is mesenchymal cell neoplasm.