Abstract: Sacoidosis is a systematic disease that can involve multiple organs including lymph nodes, lungs, liver, spleen, heart and kidneys, etc. Lymph nodes and lungs are the most common involved places and lymphadenopathy in the mediastinum and bilateral hilum with or without lung invasion is the typical manifestation. It is difficult to differentiate the atypical sarcoidosis and other multiple systems involved disease, such as lymphoma, tuberculosis and lung cancer with metastasis. Two cases and their PET/CT imaging were presented here to discuss and help with differentiation and diagnosis of sarcoidosis in clinical practice.