抄録
An aysmptomatic 59-year-old man was referred to our hospital after esophageal abnormality was detected during a medical check-up. GI tract survey revealed a 5cm diameter submucosal tumor （SMT） in the middle to lower thoracic esophagus. Chest CT, MRI and FDG-PET examinations showed no distant organ metastasis or lymphadenopathy. In order to obtain pathological information preoperatively, we performed endoscopic ultrasound （EUS） and fine-needle aspiration biopsy under ultrasound （EUS-FNAB） on the esophageal SMT. Histopathological examination of the EUS-FNAB showed spindle cells positive for c-kit and CD34, and esophageal GIST was diagnosed. MIB-1 index of the FNAB specimen was less than 2％ of the tumor cells. Esophagectomy with gastric tube reconstruction was performed. The SMT was found to be 54×45×35 mm in size. The number of mitosis was 4 per 50 HPFs and the MIB-1 index of the resected specimen was less than 2％. The final risk classification was intermediate and no adjuvant chemotherapy was administered. According to guidelines for management of patients with GIST, preoperative diagnosis is considered the first step in therapy and optimal management is based on risk evaluation after tumor resection. Sensitivity of pathological diagnosis by FNAB of the tumor is not high；EUS is merely a useful adjunct to preoperative diagnosis. Adequate specimen size may be utilized to diagnose GIST and possibly evaluate risk classification by MIB-1 index.
