A Giant Gastric Gastrointestinal Stromal Tumor Successfully Resected Following Neoadjuvant Treatment With Imatinib Mesylate

Background Neoadjuvant treatment with imatinib mesylate (IM) has not been established for gastrointestinal stromal tumor (GIST). A case of a giant gastric GIST that was radically resected following neoadjuvant therapy with IM is reported. Case report A 71-year-old woman with abdominal distension was referred to our hospital for treatment. Contrast-enhanced computed tomography showed a large (>30 cm), heterogeneous mass, with dilated vessels around the tumor. The diagnosis was a gastric GIST by endoscopic ultrasound-fine needle aspiration, and neoadjuvant therapy with 400 mg IM daily was started. Radical surgery was performed after 13 months. Since the tumor was not invasive, complete resection by partial gastrectomy was achieved without the need for combined resection of other organs. The patient remains alive without recurrence 12 months after surgery. Conclusion A giant GIST, larger than 30 cm in size, is quite rare. Neoadjuvant IM treatment should be considered in the management of large GISTs.