Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors are uncommon tumors of mesenchymal origin, arising from the intestinal tract. Prior to their recognition as a distinct biological subtype, they were termed leiomyosarcomas, leiomyomas, or leiomyoblastomas. Several findings have dramatically altered contemporary diagnostic and management strategies. First, Mazur and Clark determined that these tumors contained both smooth muscle and neural features and reclassified them as gastrointestinal stromal tumors. Subsequently, these tumors were found to express CD34 and KIT, further aiding in their classification. Finally, Hirota and colleagues determined that a majority of tumors contained KIT mutations, leading to constitutive activation of the molecule. These three findings aided pathologists in making the correct diagnosis and the selection of appropriate patients for KIT-targeted therapy. Since then, KIT-targeted therapy has significantly changed the management and prognosis of gastrointestinal stromal tumor patients.