A 64-year-old man had dysphagia and underwent gastroendoscopy. A submucosal tumor with bridging folds was found from the middle to the lower esophagus. Although fine needle aspiration biopsy revealed esophageal leiomyoma, FDG-PET/CT showed high-level FDG accumulation with a maximum standardized uptake value of 11.3 in the tumor and the tumor was suspected to be malignant such as leiomyosarcoma. Enucleation was performed but no malignant intraoperative findings were found. The tumor was 6.5 cm in diameter, consisted of spindle-shaped cells, positive for α-SMA, weakly positive for desmin but negative for CD34, c-kit and S-100 on immunohistochemistry. The Ki-67 index was 3%, and a diagnosis of leiomyoma was made. Immunohistochemical staining showed glucose transporter-1 expression in cell membranes. We should consider the differential diagnosis for chest neoplasms remembering that benign esophageal leiomyomas are potential causes of false-positive FDG-PET.