Curved nails are not necessarily lung cancer. It is also possible that lung cancer patients have bent nails, for example, patients have other peripheral neuropathy or hypocalcemia, which can cause bent nails, and other skin diseases should be excluded. Lung cancer belongs to a kind of malignant tumor of respiratory system, usually there may be no obvious symptoms in the early stage, and many people find it when they do chest CT for physical examination, so they can not diagnose lung cancer based on the symptoms such as curved nails. If occupying lesions are found in lung CT, it is necessary to do enhanced CT examination as soon as possible. If there is a burr-like appearance around the mass, it suggests that it may be lung cancer, and it is necessary to take pathology as soon as possible, including bronchoscopy or percutaneous lung aspiration to take pathology to confirm the diagnosis.