The two cases of pediatric/young adult GIST without the other components of CT showed all the features of the triad: female gender, young age, multifocal antral-based gastric GIST with biphasic histological growth pattern, lymph node metastases, hypercellularity and WT status for common KIT-, PDGFRA- and B-RAF mutations. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.