イマチニブが著効し長期完全寛解（CR）を維持している小腸GIST 腹膜播種再発の1例

We report the case of a patient with recurrent gastrointestinal stromal tumor （GIST） complicated with peritoneal dissemination who achieved long-term complete remission （CR） with imatinib mesylate therapy. A 64-year-old man was admitted to our hospital because of severe abdominal pain. Abdominal computed tomography （CT） showed free air and an intra-abdominal abscess. Perforation of the small intestine was diagnosed, and an emergency operation was performed. Two adjacent tumors （each,6cm in size）, one of which was ruptured, were found by laparotomy in the jejunum and as a peritoneal dissemination. Jejunojejunostomy with the two adjacent tumors was performed and as much of the disseminated tumors as possible were resected. Histopathological analysis indicated a high-risk GIST of the small intestine.
Abdominal CT at 1.5 years after the initial operation showed multiple recurrent tumors due to peritoneal dissemination. The patient subsequently received imatinib mesylate therapy at 400mg/day, and 5 months later, abdominal CT showed no evidence of tumor recurrence. DNA analysis of the tumor revealed an exon 11 mutation in the c-kit gene. The patient continues to receive imatinib mesylate therapy （400mg/day）, and CR of the recurrent tumors has been maintained for 8 years and 7 months.