How Worried Should I Be for a Malignancy?

A CT of the chest, abdomen and pelvis with contrast showed the following: A heterogeneous bulky, five centimeters by six centimeters by four centimeter mass. The mass abuts the pericardium, but does not appear to invade into it. There is some compression, but no occlusion of the SBC. Given the location in the anterior and middle media stynum, the mass likely represents a conglomerate of lymph node tissue.