Solution: Thymic cysts can be congenital or acquired. If acquired, they are usually related to treated Hodgkin\'s disease. They are usually well-defined with a thin imperceptible wall and they are fluid attenuation centrally. However, if there has been associated hemorrhage or infection, they can become more complicated and curvilinear calcifications like this are present in a minority of cases. Of course, the differential based upon the CXR includes the terrible T\'s: Thymus masses, Teratoma, Terrible Lymphoma, and Thyroid masses. Here is the CT image from this case.