Sarcoidosis is a well-recognized granulomatous disease that causes enlarged lymph nodes (lymphadenopathy) in the hilar region of the lung. In some individuals the disease affects the spongework of the lung (parenchyma) and causes restrictive lung disease (see Section II and the chapter Cardiomyopathy). Sarcoidosis involvement of the lung may be confused with tuberculosis, lymphoma or cancer.
The granulomatous involvement of the myocardium and conducting tissue may cause atrioventricular block and complete heart block which requires an electronic pace¬maker. Sarcoidosis may cause dilated cardiomyopathy that may be difficult to distinguish from idiopathic dilated cardiomyopathy. Prednisone produces beneficial effects in some patients.