Abstract
A 78-year-old male had small intestinal GIST with liver and peritoneal metastases and underwent surgical resection of the small intestine and some disseminated masses. He remained well for 20 months owing to the treatment with 400mg of imatinib before PET/CT disclosed a solid mass with a high FDG uptake in the left upper abdomen. Under a diagnosis of secondary resistant GIST, the PET-positive mass was selectively removed with the adjacent intestine as surgical intervention. The resected tumor was classified as KIT positive GIST and had KIT exon9 mutation (6bp insertion) on gene type analyses. Treatment with 400mg of imatinib restarted after operation and the patient's disease has been stable for six months since imatinib was restarted. As PET/CT imaging can provide early and precise local information for secondary resistant GIST, it enables surgical resection of local progressing lesions and continuation of imatinib. This might be the most rational therapeutic strategy among those currently available for secondary resistant GIST.
