LAUSR

Simple Summary Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs mainly develop in older adults, and the median age of diagnosis is 60–65 years. The incidence of GISTs in young adult patients, defined as adults before 40, is less than 10%. The frequency and type of molecular abnormalities in this group of patients are different from those in older patients. In this publication, we focus on the specificity of GISTs in young people and the principles of therapeutic management and management of the side effects of treatment. Abstract Gastrointestinal stromal tumors (GISTs) originate from Cajal’s cells and are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs in young adults, i.e., patients before the age of 40, are rare and differ from those in older patients and GISTs in children in terms of the molecular and clinical features, including the location and type of mutations. They often harbor other molecular abnormalities than KIT and PDGFRA mutations (wild-type GISTs). The general principles of therapeutic management in young patients are the same as in the elderly. Considering some differences in molecular abnormalities, molecular testing should be the standard procedure to allow appropriate systemic therapy if needed. The optimal treatment strategy should be established by a multidisciplinary team experienced in sarcoma treatment. The impact of treatment on the quality of life and daily activities, including the impact on work, pregnancy, and fertility, in this patient population should be especially taken into consideration.