High-density shadow in the lung is not necessarily lung cancer, but may be calcified foci. In addition, cancer usually requires specific mass nature. Simple high-density shadow or low-density shadow cannot indicate that it is lung cancer, but there must be clear occupancy, through which biopsy pathology puncture can be performed, and then see which type of tumor or benign tumor it is. Lung cancer is generally a malignant tumor originating from epithelial tissue, while there are benign or malignant lung tumors, and malignant tumors of the lung are usually called lung cancer. However, not all malignant tumors of the lung are lung cancer, including sarcoma of the lung, which is derived from mesenchymal tissue, which is also a type of malignant tumor, but it is not the same as lung cancer and the treatment is also different.