Korean Guidelines for the Diagnosis and Management of Interstitial Lung Diseases: Sarcoidosis.

Sarcoidosis is a granulomatous inflammatory disease of unknown etiology that can affect the entire body, but its respiratory tract involvement is most common. In radiological findings, bilateral hilar and mediastinal lymph node enlargement is the most common finding, and when lung parenchyma is involved, findings such as micronodules, ground-glass shadows, reticular shadows, and fibrosis are seen. Biopsies for histological diagnosis are mainly performed on lymph nodes or lungs, and mediastinal lymph node biopsies are done via endobronchochial ultrasound-guided fine needle aspiration. Pathological findings are characterized by non-caseating, non-necrotizing granulomas, and in Korea, differentiation from tuberculosis is especially important. The natural history of sarcoidosis is very variable, with approximately two-thirds of subjects showing spontaneous remission and only 10% to 30% of patients showing a chronic or progressive form. The most important factor in determining treatment for sarcoidosis is whether there is a risk of death, organ failure, or loss of quality of life. Glucocorticosteroids are the mainstay of treatment, and if the disease progresses despite treatment, or if glucocorticosteroids cannot be reduced or cannot be used, immunosuppressants such as methotrexate and azathioprine can be considered. Response to glucocorticosteroids treatment is good, and most of the patients stabilize or improve, with a low mortality rate of around 3% to 5%.