Since they were described, gastrointestinal stromal tumors (GISTs) are, for pathologists and not only for them, a subject of controversy regarding histological origin, differentiation, nomenclature, malignant potential and prognosis. Before 1998, there were no certainties that GISTs were fundamentally different from other types of abdominal cancers in the big family of mesenchymal tumors. Before the discovery of KIT gene mutations, GISTs were most often classified as leiomyoma, leiomyosarcoma, leiomyoblastoma, and gastrointestinal autonomic nerve tumor. When a tumor is discovered, the first data obtained are initially assessed by one or more imaging tests, such as an ultrasound, computed tomography scan or magnetic resonance imaging. The imaging results define the size of the lesion and its anatomic location, which in the case of GIST is usually within the wall of the stomach or intestine. Depending on the experience of the medical team - radiologist, gastroenterologist or surgeon - reviewing the imagistic tests and correlating them with the general patient profile, the differential diagnostic is reduced and GIST may become the main suspect.