A 65-year-old coal miner is admitted for evaluation of chronic lung disease. The patient admits to smoking one pack of cigarettes a day for 40 years. On physical examination, he is noticed to have a barrel chest and use accessory muscles for inspiration. His face is puffy and red. He has 2+ pitting edema of the lower extremities. A chest X-ray is compatible with diffuse fibrosis, with some nodularity in central areas. Which of the following is the most likely diagnosis?

Coal workers' pneumoconiosis is lung disease caused by inhalation of coal paicles and other admixed forms of dust. Coal workers' pneumoconiosis is also known as "black lung disease" due to massive deposits of carbon paicles. Complicated coal workers' pneumoconiosis (progressive massive fibrosis) occurs on a background of simple disease and generally requires many years to develop. In a minority of cases (fewer than 10%), progressive massive fibrosis develops, leading to increasing pulmonary dysfunction, pulmonary hypeension, and cor pulmonale (symptoms in the given case). The characteristic pulmonary lesions include palpable coal dust nodules scattered throughout the lung as 1- to 4-mm black foci. Nodules consist of dust-laden macrophages associated with a fibrotic stroma.