Intrapulmonary nodules, usually defined as substantial lesions in the lungs with a diameter of less than 3 cm, are a common yet difficult to diagnose disease in thoracic surgery and have always been a difficult clinical problem. Intrapulmonary nodules can be benign or malignant. Benign lesions mainly include inflammatory pseudotumor, misshapen tumor, tuberculous ball and hemangioma. If malignant, they may be primary lung cancers, such as lung adenocarcinoma or fine bronchioloalveolar carcinoma, or they may be metastatic malignant tumors from other parts of the body that have metastasized to the lungs. Is it possible for isolated lung nodules to be malignant? According to the literature, about 40% of isolated lung nodules are eventually confirmed to be lung cancer. When the patient’s age is >45 years old, more than 60% of isolated lung nodules are malignant; when the diameter of the nodule is >1cm, more than 80% of isolated lung nodules are malignant. Attention should be drawn to patients with the following clinical manifestations: age ≥45 years old, symptoms such as blood in sputum, dry cough, fever, chest pain, and signs such as gynecomastia and pestle-like fingers (toes). In addition, patients with a history of smoking, tuberculosis, tuberculosis exposure, and a family history of tumors need to be vigilant, and a history of these diseases is helpful in making a diagnosis. On imaging, the main malignant signs of lung nodules include lobulation, fine short burrs, vacuolar sign, pleural depression sign, concentration of pulmonary vessels, and marked enhancement of the lesion. The CT signs of benign tumors are smooth and sharp contours, no burrs, uniform density, and pleural depression without pleural depression incision, and the diagnostic compliance rate is relatively high. Inflammatory nodules are characterized by clear margins, burrs, uniform density, smooth and sharp contours, spicules and pleural recesses without pleural recesses.