A 51-YEAR-OLD white man with a 45-year history of smoking was noted to have an abnormality on a routine chest x-ray. He denied any history of cough, sputum production, chest pain, dyspnea, weight loss, weakness, or tuberculosis. There was no previous chest x-ray available for comparison. The patient's physical examination results were unremarkable. His chest x-ray is shown in Figure 1and a computed tomographic (CT) scan of his chest is shown in Figure 2.