2015 Volume 54 Issue 7 Pages 759-764
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Since our first report in 1998, approximately 30 families with multiple GISTs due to a germline gain-of-function mutation of c-kit have been reported. We herein present a case of a family with multiple GISTs that have a germline c-kit mutation in exon 11 (Del-Val560) in two siblings. One of the patients showed a fair response to treatment with a half-dose of imatinib (200 mg/day). There are few reports describing the response to imatinib in familial GISTs and this drug appears to be a promising therapeutic option.