Sarcoidois is an idiopathic disorder characterized by non-caseating granulomatous inflammation in multiple organs. An abnormal immune response to inhaled antigens, possibly mycobacteria, may cause the disease. North American blacks (women in particular) and Northern European whites are commonly affected. Thoracic involvement occurs in 90% of cases. The disease may follow a benign course (granulomas resolve in 80%) or may cause progressive fibrosis, bullae, and bronchiectasis.

·   Laboratory findings - Serum calcium, urine calcium, and serum ACE may be elevated. However, these findings are not sensitive or specific. Diagnosis usually requires biopsy demonstrating non-caseating granulomas.
·   Mediastinal and hilar adenopathy are the most common radiographic findings, seen in 75-80% of patients. Symmetric hilar, paratracheal and subcarianl adenopathy is classic.
·   Pulmonary parenchymal findings may be divided into reversible and irreversible changes. Reversible changes include reticulonodular opacities and large nodules. Irreversible changes consist of pulmonary fibrosis, bronchiectasis, and bullae formation.
·   Staging of thoracic sarcoidosis according to DeRemee's classification is based on the chest radiograph
o   Stage 0 - normal radiograph
o   Stage 1 - hilar and/or mediastinal adenopathy
o   Stage 2 - pulmonary opacities with adenopathy
o   Stage 3 - pulmonary opacities without adenopathy

·   Other radiographic findings:
o   Pleural effusion - 10%
o   "Eggshell" lymph node calcification
o   Pneumothorax (as a complication of bullous disease)
o   Bronchial obstruction/lobar collapse
o   Mycetomas
·   Treatment, when required, consists of oral corticosteroid therapy.