Pulmonary nodules are round or irregular shaped lesions less than or equal to 3cm (i.e., 30mm) in diameter in the lungs, which appear as shadows of increased density on imaging, and may be single or multiple, with clear or unclear borders, and are not accompanied by pulmonary atelectasis, hilar lymph node enlargement, or pleural effusion.
There are numerous etiologic factors leading to pulmonary nodules, which can be classified into benign and malignant pulmonary nodules according to the benignity or malignancy of the nodules. Among malignant lung nodules, most are primary lung cancers, with adenocarcinoma being the most common. Benign nodules, on the other hand, have more causes and can be caused by benign tumors, infections, etc., as well as inflammatory, vascular or congenital lesions.
Lung nodules can also be categorized according to size. A diameter of less than 5mm is defined as a microscopic nodule, and a diameter of 5-10mm is defined as a small nodule. Lung nodules larger than 8mm in diameter have a relatively higher risk of malignancy, and relevant examinations should be performed to clarify the nature of the nodule.
It is recommended to have regular medical checkups, and if lung nodules are found, consult the doctor promptly and follow the doctor’s instructions for active treatment.