Chest radiograph of an adult patient. There is an abnormal mass situated in the centre of the chest. This does not cause obscuration of the descending thoracic aortic arch. The hilar vessels are seen clearly. There is however loss of the ascending aortic arch. The appearance on imaging is suggestive of an anterior mediastinal disease process. Differential diagnosis includes thymoma, lymphoma or teratoma. A focal nodule appears to be present adjacent to the 2nd right posterior rib. No additional lung nodules appreciated. No lytic or destructive bony changes. Both breast shadows are intact. I would suggest a CT scan of the chest abdomen pelvis for further assessment.