Contrast enhanced CT of the chest obtained in a patient with Hodgkin lymphoma shows a confluent mass (arrows) in the mediastinum anteriorly. The mass indents the superior aspect of the left brachiocephalic vein (asterisk). Small amount of pleural effusion is seen on the left side. It is to be noted that a mass originating in the mediastinum forms an obtuse angle with the adjacent lung, often has a smooth contour and can extend across the midline involving both hemithoraces. On the other hand, an intra-pulmonary mass forms an acute angle with the adjacent lung, does not extend across the midline, and may contain an air-bronchogram