Fig. 1
Radiographic imaging findings. a Chest X-ray showed an abnormal opacity in the mediastinum at the patient’s first visit to our hospital. b Chest contrast-enhanced computed tomography showed a mass with a maximum diameter of 5.2 cm in the anterior mediastinum. The lesion was extensively in contact with the sternum on the ventral side and partly in contact with the trachea on the dorsal side, between the brachiocephalic and the left common carotid arteries. c 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) showed high FDG uptake (maximum standardized uptake value was 6.71) in the anterior mediastinal mass and sternal infiltrate