Ground glass nodule 0.5cm is not necessarily early stage of lung cancer, but may also be lung hemorrhage, atypical adenomatoid hyperplasia, etc. 1. Peripheral lung cancer: Early stage is asymptomatic, some patients may have symptoms such as cough, chest tightness, etc. Imaging manifestation is mostly nodular, and ground-glass nodules are mostly seen in lung adenocarcinoma, with clear edges of the lesion, often accompanied by burr sign and lobulation sign. 2. Pulmonary hemorrhage: when there is alveolar hemorrhage or rupture of pulmonary static artery which leads to pulmonary hemorrhage, hemoptysis, dyspnea and other clinical manifestations can occur, and the CT manifestation can be ground glass nodules, solid nodules, flaky ground glass shadows and other manifestations. 3. atypical adenomatous hyperplasia: it is a precancerous lesion of lung adenocarcinoma, and has a certain chance of transforming into lung adenocarcinoma, which is often manifested as ground-glass nodular shadow on CT. Pale glass nodules can be caused by many kinds of diseases, not necessarily caused by lung cancer at early stage. However, the larger the diameter of ground-glass nodule is, the higher the possibility of malignancy, so you should go to the hospital as soon as possible for examination to clarify the cause of the disease, so as to avoid delaying the condition.