When many people find small shadows in the lungs during chest X-ray or medical checkup, many people immediately associate it with the word “lung cancer” and are scared half to death. In fact, such small shadows in the lungs are medically called small lung nodules, which usually do not have any symptoms or discomfort, but are only found by chance during physical examinations, and most of them are one to two centimeters in size. Small lung nodules are not necessarily lung cancer. Benign pulmonary nodules include pulmonary malignant nodules, bronchial adenomas, inflammatory lesions (also known as inflammatory pseudotumors), tuberculomas, etc. These benign pulmonary nodules are harmless to human body and rarely cause clinical symptoms. Malignant small lung nodules include small lung cancer or early lung cancer, and metastatic cancer of the lung. In general, benign nodules and malignant nodules in the lung account for a certain percentage of each, so if small lung nodules are found on physical examination, people should not worry too much. Most of the patients who come to the thoracic surgery department are found to have small nodules in the lungs by chest X-ray or CT scan. When small lung nodules are found, it is important to pay attention to whether there are some risk factors for lung tumors, such as old age, long-term smoking history or second-hand smoke, too much fumes inhalation, and previous malignant tumors in other areas. Small nodules in the lung should not have symptoms, but many people will “feel” many symptoms, including chest pain and cough, once they know they have small nodules in the lung. If you find a small nodule in your lung during a physical examination, don’t be nervous, you can get a chest enhancement CT to determine it. To determine whether a small lung nodule is benign or malignant, it is most important to compare the size, morphology and marginal structure of CT imaging. In malignant pulmonary nodules, there are some “burrs” around the edges, like hair strands, with unclear borders; in benign pulmonary nodules, you can sometimes see signs of calcification, and the nodules are relatively round with clear borders. There are also small solid nodules that look like “frosted glass”, a faint shadow, this kind of nodules should be very careful, the probability of tumor is higher. In addition, we should dynamically observe the growth rate of this small lung nodule, if it increases rapidly and grows more than 20% within a few months, it may be a malignant lesion; if it does not change much within one or two years, there is no need to worry. The patient could be observed, but he was under great psychological stress and the two small nodules were affecting his normal life and emotions. In this case, the specialist performed minimally invasive surgery to remove the two small nodules for biopsy, and the patient was very happy that the results were benign. The U.S. guidelines for the treatment of pulmonary nodules suggest that if there are no high-risk factors when a small nodule is found, it is perfectly acceptable to follow up with a CT scan of the chest every three to four months for one and a half to two years, and if there is no change for two years, you can rest assured. However, if it is a small frosted glass-like nodule, despite no increase in size within six months, it is still important to continue observation. Clinical findings show that screening by low-dose chest CT has a much higher detection rate than chest X-ray, which can only detect small lung nodules of 1 cm or 1.5 cm or more. Therefore, to identify benign or malignant small lung nodules, it is actually best to do a chest CT enhancement. Enhancement imaging is an important marker to identify whether it is malignant, and in addition, blood can be drawn for tumor marker testing, such as carcinoembryonic antigen, squamous carcinoma antigen, cytokeratin 21 and other indicators.