Glucose Transporter Expression of an Esophageal Gastrointestinal Tumor Detected by F-18 FDG PET/CT

A 74-year-old woman had dysphagia and underwent esophago-gastroduodenoscopy. A giant submucosal tumor was seen from the middle to the lower esophagus. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG-PET/CT) was performed and F-18 FDG was found to accumulate in the submucosal tumor. The maximum standardized uptake value of the early phase was 4.93 and that of the delayed phase was 6.48. Gastrointestinal stromal tumor (GIST) was confirmed by both fine needle aspiration under endoscopic ultrasound and postoperative histopathologic findings. We stained the postoperative histopathologic specimen to investigate glucose transporter (GLUT) expression using immunohistochemistry, which revealed that GLUT-1 had a weak expression on membranes and GLUT-4 had a strong expression on membranes or in cytoplasm. GLUT-3 had no expression on membranes or in cytoplasm. Esophageal GIST is rare and the relationship between GLUT expression and F-18 FDG accumulation in GIST is probably rare.