The sudden appearance of a 1.1cm solid nodule in the left lung may be due to inflammation or tumor and other diseases. 1. Nodule caused by inflammation: it should be considered as a result of lung infection, tuberculosis and other diseases, the edge of the nodule is smooth, the border is clear, and the patient is mostly accompanied by respiratory symptoms such as coughing, coughing up sputum, fever, etc. After regular and effective anti-infection and anti-tuberculosis treatments, the inflammatory nodule will be gradually reduced or even completely disappeared. 2. Tumor-induced nodules: Tumors can be divided into benign tumors and malignant tumors. Benign tumors mostly have envelope, smooth and sharp edges, and malignant tumors can be seen as “popcorn”-like calcification. Malignant tumors are mostly infiltrative growth, with rough edges and burrs, and can be connected with the pleura to form pleural depression sign. Although the patient had respiratory symptoms, anti-infection and anti-tuberculosis treatment was ineffective. The sudden appearance of a 1.1-cm solid nodule in the left lung should be seen in the hospital immediately to clarify the cause of the disease. Treat the cause and symptoms.