GIANT CORONARY-ARTERY ANEURYSM PRESENTING AS A MEDIASTINAL MASS

A fit and well 72-year-old white man with an abnormal chest radiograph was referred to the cardiology clinic for assessment of probable righ t heart enlargement. There was no preceding history of pulmonary hyper tension or coronary artery disease. Blood pressure was 115/70 mm Hg. P recordial auscultation disclosed no abnormalities. There were no signs of pulmonary hypertension. There were no electrocardiographic feature s of myocardial ischemia or infarction. Chest radiography (Figure 1, p anel A) showed an abnormal prominence of the right heart border. Trans thoracic echocardiography revealed a cystic cavity adjacent to the rig ht atrium. Computerized tomography of the thorax revealed a spherical mass (dimensions 6.5 x 8.5 cm), lying anterior and lateral to the righ t atrium (Figure 1, panel B). Dynamic intravenous contrast injection r esulted in enhancement of the mass with similar timing and density to the heart chambers. Magnetic resonance imaging showed the proximal rig ht coronary artery adjacent to the mass (Figure 1, panel C). Using a c ine gradient echo technique, blood flow was clearly demonstrated withi n the mass (Figure 1, panel D), suggesting the diagnosis of a very lar ge right coronary aneurysm. Cardiac catheterization was performed from the right fem oral artery. There was diffuse atheromatous change with severe ectasia throughout the left coronary artery. The proximal righ t coronary artery opened into a large, spherical cavity which filled w ith contrast medium in a swirling fashion, with slow opacification of the distal right coronary artery (Figure 1, panel E), confirming the d iagnosis of a giant right coronary artery aneurysm. At surgery, a larg e, spherical mass was present anterior to the right atrium. Cardiopulm onary bypass was established and the aneurysm was incised. The wall wa s thin, and atheromatous plaque was present. The right coronary artery lumen was identified, the proximal and distal ends were mobilized, an d an end-to-end anastomosis was performed. Postoperative recovery was uneventful and repeat right coronary arteriography before discharge sh owed a widely patent anastomosis and good flow into a large distal ter ritory.