A left pulmonary nodule is a small nodular lesion on the left side of the lung found on a chest CT scan. Lung nodule is the short name of medical imaging for a nodule with a diameter of 5~10 mm, which usually appears as a rounded shape and can be single or multiple, and the specific cause of the disease needs to be further examined. There are many causes of pulmonary nodules, common inflammation, tuberculosis, mycobacterial infection. Diseases include inflammatory pseudotumor, misshapen tumor, tuberculosis ball, fungal infection, sclerosing pneumocytoma, etc. It may also be primary lung cancer or metastatic cancer within the lung. Small nodules in the left lung may also be other lesions, such as silicosis. You should go to a regular hospital in time, and the doctor will diagnose the disease according to the specific conditions of the nodule and give treatment.