What is sarcoidosis?

Sarcoidosis (sar-coy-DOE-sis) is a disease of unknown cause in which inflammatory cells clump together and form tiny lumps of cells in various organs and tissues of the body. These lumps are called granulomas (gran-yu-LO-mas). Sarcoidosis most often affects the lungs and its hilar lymph nodes but can also involve other areas of the body including the eyes, skin, sinuses, liver, kidneys, brain and heart. Sarcoidosis varies in how active and how severe it is for each person and over time. The granulomas, when active, can cause short term and/ or long term damage to the organ involved. This fact sheet provides a general overview of sarcoidosis. For more information about treatment of sarcoidosis, see Treatment of Sarcoidosis at www.thoracic.org/patients.