Possible causes of right subpleural nodular shadow include lung inflammation, tuberculosis, lung cancer, lung metastases and so on. 1. Lung inflammation: when lung inflammation causes local tissue exudation, it can be manifested as nodular shadow on imaging, especially viral pneumonia is common. In addition, small nodules can also be formed when the inflammatory lesion is wrapped by hyperplastic fibrous tissue. 2. Tuberculosis: caseous necrotic foci of tuberculosis can be wrapped by fibrous tissue to form isolated foci with clear boundaries, called tuberculosis balls, which can be seen as nodular shadow on imaging. 3. Lung cancer: when the tumor size of lung cancer is not big, it can be shown as nodular shadow on imaging, and it is mostly in the early stage of the tumor. 4. Lung metastases: malignant tumors in other parts of the body can be transferred to the lungs through the bloodstream to form nodular metastatic foci, such as osteosarcoma, soft tissue sarcoma, uterine choriocarcinoma, etc., which are mostly multiple nodular shadows. It is recommended to go to the hospital as soon as possible to clarify the nature of nodules and give targeted treatment.