A 74-year-old man presented with a 2-year history of gradually increasing dyspnea on exertion. Before retiring from his construction job, he worked with asbestos insulation for 36 years. His chest x-ray revealed bibasilar linear opacities and changes consistent with mild fibrosis (Figure 1). Pulmonary function test results were consistent with restrictive lung disease. Bronchoscopy with bronchoalveolar lavage (BAL) yielded negative cultures but revealed a positive finding that supports the diagnosis (Figure 2).