PDGFRA and neurofibromatosis: Imatinib is the treatment of choice in this setting; however, tumors that have a platelet-derived growth factor receptor-alpha (PDGFRA) D842V mutation, or a succinate dehydrogenase (SDH)-deficient or neurofibromatosis (NF)-related GIST, are considered resistant to imatinib and will not benefit from neoadjuvant treatment; in these cases, upfront surgery is recommended.