Sarcoidosis affecting predominantly the lungs, the site most frequently involved and most commonly causing morbidity and mortality in sarcoidosis. Pulmonary sarcoidosis is characterized by sharply circumscribed granulomas in the alveolar, bronchial, and vascular walls, composed of tightly packed cells derived from the mononuclear phagocyte system. The clinical symptoms when present are dyspnea upon exertion, nonproductive cough, and wheezing. (Cecil Textbook of Medicine, 19th ed, p431)