Inoperable c- kit negative gastrointestinal stromal tumor (GIST) is commonly considered to be highly resistant to systemic therapy. We present a case of a woman with an abdominal sarcomalike tumor diagnosed at the age of 26. The patient underwent several surgical procedures and courses of cytostatic therapy without any substantial effect. Later, the tumor was reclassified as c- kit negative GIST harbouring the mutation in exon 12 of PDGFRA gene. Hence, the therapy with imatinib mesylate was initiated, resulting in partial remission of metastatic lesions and further stabilization of the disease for five years to date. We therefore consider imatinib mesylate an appropriate therapy for c- kit negative GIST bearing PDGFRA mutations.