Lesions of the thoracic aorta and its arch branches simulating neoplasm.

Abnormal radiographic densities in the midportion of the chest are most commonly caused by neoplasms, cysts, or inflammatory disease. However, vascular lesions may present an identical x-ray appearance, with no distinguishing clinical history or physical findings. The cardiothoracic surgeon must be aware of this similarity in order to ensure the most appropriate diagnostic and therapeutic approach. In our experience, the most frequent problem in differential diagnosis is a lesion of the thoracic aorta or its arch branches simulating neoplasm. Nine such cases are presented, with pertinent conventional radiographs angiograms, and computed tomographic (CT) scans. These are considered in anatomic sequence: (1) ruptured sinus of Valsalva aneurysm; (2) ascending aortic aneurysm; (3) tortuosity or aneurysm of the innominate and subclavian arteries; (4) transverse arch aneurysm; (5) pseudocoarctation; and (6) descending aortic aneurysm. Such vascular lesions must be considered early in the evaluation of any juxta-aortic chest density, particularly if the patient is hypertensive and has other manifestations of atherosclerosis. Angiography and computed tomography establish the diagnosis in most instances, although both are less reliable when thrombus fills all or part of an aneurysm. If these methods fail to establish a vascular origin, the possibility of neoplasm is pursued. When neither a vascular nor neoplastic origin can be proved, surgical exploration is indicated in the otherwise good-risk patient.