Recurrence of gastric gastrointestinal stromal tumor 12 years after repeat hepatectomies for liver metastases: report of a case

No consensus has been reached on the postoperative treatment and follow-up duration for high-risk malignant gastrointestinal stromal tumor (GIST). We herein report a case of recurrent liver metastasis from gastric GIST in a patient who had been receiving adjuvant chemotherapy with imatinib mesylate for 10 years. A 78-year-old woman underwent local gastrectomy for a 20-cm gastric GIST with a mitotic index of 25/50 high-power fields (HPF) 17 years before. Partial hepatectomy for recurrent liver metastases was repeatedly performed 14 and 12 years before. After the second hepatectomy, postoperative adjuvant chemotherapy with imatinib mesylate was given for 10 years, during which no recurrence was observed. Two years after the completion of adjuvant chemotherapy, computed tomography revealed a 2-cm hepatic tumor; thus, laparoscopic partial hepatectomy was performed. Histopathological findings revealed a liver metastasis of gastric GIST with a mitotic count of 20/50 HPF and MIB-1 labeling index of 20%. Mutation analysis of the KIT gene revealed an exon 11 mutation. The patient is currently undergoing postoperative adjuvant chemotherapy with imatinib mesylate. The combination of surgery and long-term adjuvant chemotherapy for high-risk malignant GIST and liver metastases may be effective to achieve a good prognosis.