[Medical Q&A] What exactly are lung nodules?

Planner: Chinese Medical Association

Reviewer: Zhou Xin, Chief Physician, First People's Hospital, Shanghai Jiao Tong University School of Medicine

With the widespread use of low-dose CT in physical examinations, more and more people are beginning to understand "lung nodules".

Pulmonary nodules are essentially an imaging concept, referring to round or irregular abnormal shadows with a diameter of less than 3 cm found in lung imaging examinations (such as X-rays or CT scans). Imaging examinations cannot yet clarify their specific nature, so they are described as pulmonary nodules. In general, masses with a diameter of ≤3 cm are called pulmonary nodules, while those with a diameter of >3 cm are called lung masses. Abnormal cell proliferation and differentiation, inflammatory response and repair response, immune response, etc. caused by various reasons are the formation mechanism of pulmonary nodules. Pulmonary nodules can be divided into benign and malignant: those caused by infection, inflammation, benign tumors (such as hemangiomas, fibromas, etc.) are mostly benign nodules; those caused by primary lung cancer, metastatic lung cancer, etc. are mostly malignant nodules. According to the nodule density of imaging examinations, pulmonary nodules can be divided into solid nodules, partially solid nodules, and ground glass density nodules. Most patients with pulmonary nodules are asymptomatic, usually accidentally discovered during routine physical examinations or imaging examinations for other reasons. A few patients will have symptoms such as cough, dyspnea, chest pain, and fever. In addition to imaging examinations, pathological examinations and other methods are also diagnostic methods for lung nodules. It is important to remind you that if you find lung nodules, you don’t need to panic, because lung nodules are not necessarily lung cancer. Scientific examination methods can be used to determine the nature of the nodules, and the doctor will also formulate an appropriate treatment plan based on the actual situation.