The extra-pulmonary manifestations of lung cancer are complex and diverse clinical manifestations caused by special hormones, antigens, enzymes or metabolites produced by cancer cells, which may involve all systems of the body and are not related to the direct erosion, metastasis, obstruction and compression of lung cancer. Systemic changes: anorexia, cachexia, fever and immunosuppression. Ectopic endocrine syndrome: such as ectopic ACTH secretion, antidiuretic hormone hypersecretion, ectopic thyroxin, Cushing’s syndrome, etc. Like Cushing’s syndrome, it is caused by the increased level of antidiuretic hormone, which is mostly found in small cell lung cancer and adenocarcinoma. It secretes a large amount of antidiuretic hormone and causes hyponatremia and low plasma osmolality, resulting in symptoms such as polyuria, thirst and excessive drinking. Pestle and mortar, hypertrophic pulmonary osteoarthropathy. Pulmonary osteoarthropathy and pestle finger are signs of potential lung cancer. Pestle finger (toe) is the most common extra-pulmonary sign of lung cancer, characterized by its short-term appearance and rapid development, accompanied by obvious pain. Pulmonary osteoarthropathy is a condition of osteochondral hyperplasia and new bone formation caused by a lung tumor that begins at the end of the long bones. Squamous carcinoma is common. Neuromuscular lesions: may manifest as muscle weakness syndrome (Eaton Lamber syndrome), peripheral neuropathy, subacute cerebellar degeneration, cortical degeneration, polymyositis. V. Blood changes: may manifest as anemia, agranulocytosis (leukemia-like), erythrocytosis, etc. Coagulopathy: manifest as wandering embolic phlebitis, non-bacterial embolic endocarditis, diffuse intravascular coagulation, capillary oozing anemia, thrombocytopenic purpura. Tumor cells have the ability to promote thrombosis. The incidence of combined thrombosis in lung cancer is reported to be as high as 58%. Adenocarcinoma is the most frequent, especially mucin-secreting adenocarcinoma, which is associated with almost 100% of thrombosis of different types. The thrombotic comorbidity seen at autopsy is much higher than the prebiotic clinical diagnosis. Most thromboses are venous and rarely arterial. Therefore, lung cancer is often a cause of pulmonary infarction. Sudden onset of chest pain and drop in blood pressure in lung cancer patients. Unexplained difficulty in breathing should be thought of. VII. Skin lesions:They can be manifested as dermatomyositis, acanthosis nigricans, scleroderma, palmoplantar skin hyperkeratosis, etc. VIII. Cancerous nephropathy:manifests as nephrotic syndrome and glomerulonephritis. The extra-pulmonary manifestations appeared 12d～18 months before the respiratory symptoms, and the time of appearance of the same extra-pulmonary manifestations varied, and the time of appearance of extra-pulmonary manifestations of the same tissue type was close. The average time to appearance of extra-pulmonary manifestations varied from 3 to 4 months for squamous carcinoma, 2 to 3 months for small cell lung carcinoma, and the duration of adenocarcinoma. The first misdiagnosis rate is 95, 12%, so we should pay special attention to it!