The severity of a lung nodule cannot be judged solely by the size of the nodule.A 10mm by 13mm lung nodule may be serious if malignant or not so serious if benign. Lung nodules are high-density masses in the lungs that are detected on chest CT and X-ray and can be categorized as benign or malignant nodules. Benign nodules are common, such as pulmonary fibroma, tuberculosis ball, etc., the prognosis is relatively good, even if the size of the nodule is 10mm by 13mm, it is relatively not serious, and timely treatment and treatment, can be cured. Malignant nodules are seen in lung malignant tumors, i.e. lung cancer. When the size of nodule is 10mm by 13mm and diagnosed as lung cancer, the staging belongs to T1b stage, and if there is no lymph node and distant metastasis, it is IA2 stage lung cancer, which is early lung cancer. From the point of view of the degree of progression of lung cancer, it belongs to early stage and the condition is relatively not serious, but from the point of view of the nature of the disease, lung cancer belongs to cancer and the prognosis is not good, which belongs to serious. If the size of the nodule is 10mm by 13mm, and lymph node metastasis or distant metastasis occurs when it is diagnosed as lung cancer, it is intermediate-late stage lung cancer, which is very serious. If you find lung nodules, it is recommended to consult a doctor in time to clarify the nature of the nodules and standardize the treatment under the guidance of a professional doctor.