In today’s world where cancer is talked about, people are very concerned about their health and their awareness of cancer prevention is increasing. If a nodule is found in the lung during a medical checkup, it may make people feel frightened. One would wonder if this lung nodule is lung cancer. This is a question that many people are wondering and worried about. Today, we will learn what this lung nodule is? Is there any relationship between it and lung cancer? Lung nodule is defined as a single nodule with clear border, diameter less than or equal to 75px, and surrounded by air-containing lung tissue. There are quite a number of causes. In the vast majority of cases, lung nodules belong to benign lesions such as chronic pneumonia, inflammatory pseudotumors, tuberculosis bulbs and pneumoconiosis, which are atypical hyperplasia or fibrous lesions of the lung, or they may be malignant diseases such as early lung cancer and metastases. Thus, the nature of pulmonary nodules can be divided into two main categories: benign pulmonary nodules and malignant pulmonary nodules. 1, small lung nodules: those less than 37.5px in diameter can be called small lung nodules; 2, malignant nodules: half of the nodules above 50px are malignant; 3, benign nodules: most of the small nodules below 25px are benign. If the chest CT suggests pulmonary nodules, it may be the following diseases: 1, benign tumor: including pulmonary malignant tumor, adenoma, lipoma, infectious granuloma, pulmonary tuberculosis, pneumosporidiosis, etc. 2, benign non-neoplastic diseases: occlusive fine bronchitis with mechanized pneumonia, lung abscess, silicosis, fibrous degeneration, hematoma, inflammatory pseudotumor, pulmonary infarction, etc. 3, malignant tumors: bronchial lung cancer (adenocarcinoma, squamous carcinoma, small cell lung cancer), carcinoid tumors, pulmonary lymphoma. 4, metastatic tumors: colon cancer, breast cancer, kidney cancer, head and neck tumors metastasized to the lung. To confirm whether a lung nodule is lung cancer? CT-guided percutaneous lung aspiration biopsy is an important clinical method to confirm the benignity and malignancy of lung nodules and lung masses. It has extraordinary diagnostic value in determining the nature of lung nodules. 2. Thoracoscopy can be used as both an examination and a treatment tool, and the accuracy of diagnosis is almost 100%. Patients not only get a clear pathological diagnosis, but also can have the nodules removed through thoracoscopy. In short, having a lung nodule does not necessarily mean lung cancer. However, lung nodules are indeed one of the most common manifestations of lung cancer in its early stages, and they are highly uncertain and dangerous, so we should not be too careless.