[Successful resection of locally advanced gastrointestinal stromal tumor of the ampulla of Vater after treatment with imatinib].

Gastrointestinal stromal tumor (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract arising from Cajal's cells, expressing CD 117. The standard treatment for primary GIST is complete surgical resection. Imatinib mesylate, a specific tyrosine kinase inhibitor, is effective against locally advanced and metastatic GIST. There are several reports of the effect of preoperative imatinib in patients with unresectable and locally advanced primary GIST. We report a case of unresectable primary GIST of the ampulla of Vater, which we were able to completely resect after treatment with a dosage of imatinib 400 mg daily for 5 months. Twelve months later, the patient was treated with imatinib and doing well with no evidence of recurrence.