Plain chest x-ray can show four different stages of sarcoidosis:

• stage 1: bilateral hilar lymphadenopathy
• stage 2: bihilar lymphadenopathy and reticulonodular infiltrates of parts or the entire lung
• stage 3: bilateral pulmonary infiltrates without signs of hilar lymphadenopathy
• stage 4: fibrotic degeneration of the lung (possibly with upward hilar traction, cystic and/or bullous destruction of the lung)