Endotracheal leiomyoma is a rare benign lesion, accounting for approximately 1% of tracheal tumors, and generally occurs in the lower respiratory tract. Because its growth causes airway obstruction symptom, surgical treatment is generally suggested after detection. We report a case with leiomyoma of the cervical endotracheal space showing intense FDG uptake on F-FDG PET/CT mimicking malignancy in a 79-year-old woman with papillary thyroid carcinoma.