It is a chronic granulomatous multi-system disease of unknown cause characterized by non-ceasting granuloma. Most common in females of 20- 40 years. In 90% of cases it involves the lungs resulting in dyspnea, bilateral hilar lymphadenopathy and non-productive cough. Other systems it involves CNS (Diabetes inspiduos, space occupying lesion, facial nerve palsy) CVS (cardiac arrhythmia, heart block) Eye (uveitis) Liver (splenomegaly and granulomatous liver disease) Kidney ( nephrocalcinosis and renal stones) Skin ( erythema nodosum and lupus pernio) Bones (osteoporosis and arthropathies)