Emphysema is a chronic lung condition in which the air sacs (alveoli) may be destroyed, narrowed, collapsed, stretched, or overinflated. Overinflation of the air sacs is a result of breakdown of the walls of the alveoli. It causes a decrease in respiratory function and breathlessness. Damage to the air sacs is irreversible and results in permanent "holes" in the tissues of the lower lungs.
Sarcoidosis is a rare disease caused by inflammation. It usually occurs in the lungs and lymph nodes, but it can occur in almost any organ. Sarcoidosis in the lungs is called pulmonary sarcoidosis. It causes small lumps of inflammatory cells in the lungs. These lumps are called granulomas and can affect how the lungs work.