Two cases of primary mediastinal seminoma presented as (a) aortic aneurysm with symptoms suggestive of coarctation of the aorta and (b) nonspecific tumor mass with left diaphragmatic paralysis. By computed tomographic (CT) scans both tumors were massive with sharply demarcated borders, loss of fat planes between the tumor and surrounding organs, and homogeneous density (30 to 40 Hounsfield units) only slightly enhanced by contrast medium infusion. Such CT findings should suggest the possibility of a primary mediastinal seminoma. © 1983 Raven Press, New York.
