Malignant lung nodules, especially peripheral lung nodules, often have no obvious symptoms and are mostly detected by physical examination. As the disease progresses, clinical manifestations such as cough, e.g. irritating dry cough, will appear. Malignant lung nodules, i.e. lung cancer, often have no typical symptoms in early stage. Early stage lung cancer is usually detected through physical examination or imaging tests such as lung CT for other reasons. As the disease develops, patients will have a series of clinical manifestations, the most common symptoms include cough, mostly irritating dry cough, blood in sputum or recurrent hemoptysis. The most common symptoms are cough, mostly irritating dry cough, blood in sputum or repeated hemoptysis. Besides, it will also manifest as pestle-shaped finger, hoarse voice, shortness of breath and so on. As the symptoms of lung cancer are not specific, it is recommended to consult doctor as soon as possible to avoid delaying the condition.