Solid micronodular shadows in the upper lobe of the right lung are generally considered to be fibrous scar foci left after healing of diseases such as lung infection or tuberculosis, or may be neoplastic lesions caused by tumor proliferation. Regular outpatient follow-up of chest CT is usually needed. 1. Lung infection or tuberculosis can cause alveolar edema, necrosis and fibrin exudation during the course of the disease. If the exuded fibrin is too large to be completely absorbed by the body, it will be deposited in the lung tissue and form fibrous scar foci after healing of the disease, which will be manifested as solid micronodular shadows on imaging. 2. Early stage of lung tumor can show solid micronodular shadow, which is tumor-like hyperplastic lesion, and later development can be benign tumor or malignant tumor such as primary lung cancer or metastatic tumor. Regular outpatient follow-up of chest CT is usually required. Solid micronodular shadow in the upper lobe of the right lung is recommended for further consultation in the department of thoracic surgery or respiratory medicine.