Lung nodules that grow by one millimeter a year may be benign, but malignancy cannot be completely excluded. The diameter of lung nodules is usually below 3 centimeters, and the increase of one millimeter a year depends on the size of the specific nodule and whether there are clinical symptoms. If the lung nodule has always been small, under 8mm, for example, 5mm, and increases to 6mm, and there is no discomfort, then the possibility of benign disease is considered greater. If the diameter of the lung nodule itself is more than 8mm and continues to increase, or the imaging manifestation of the nodule presents lobular, burr-like, vascular signs, pleural pulling, etc., then consider that malignant nodules may be more likely, and even if there is no discomfort, it is still necessary to treat it at the earliest possible time. Whether the lung nodule is considered benign or malignant, it is necessary to go to a professional institution as soon as possible to be evaluated by a specialist, and then give further guidance according to the specific conditions of the individual.