What kind of disease can I have if I find an unexplained mass in my lungs? For any lung mass shadow, there are both benign and malignant possibilities. Benign disease is more common with tuberculosis and inflammatory lesions, while malignant disease is mainly lung cancer. In younger patients, benign disease is more common, while in older patients, malignant disease is more common. Recently five countries around the world collaborated on an early lung cancer action plan to detect lung masses by CT screening. The results found that CT showed a 2-5 mm lung mass shadow with a 60% likelihood of lung cancer between the ages of 40-50 years, and an 80% likelihood of lung cancer over the age of 50 years. Thus lung cancer is more prevalent in adults. Early lung cancer does not have symptoms and is usually detected by physical examination. However, early stage lung cancer can hardly be diagnosed before surgery. What should I do if I find a lumpy lung shadow? The results of this famous study concluded that the detection of lung mass shadow should be aggressively operated. The reasons for this are 1) adults who find a lung mass shadow have a high chance of lung cancer, 2) early lung cancer has an 80% chance of being completely cured by surgical resection, and most patients will not recur, and 3) current imaging methods cannot confirm the diagnosis, even PET-CT advertised by some companies. At present, the pathological methods that can confirm the diagnosis of lung cancer are fiberoptic bronchoscopy and lung puncture biopsy, but if these two methods do not find cancer cells, the possibility of lung cancer still cannot be ruled out. Moreover, for early stage lung cancer, the possibility of finding cancer cells by these two methods is very small. Since surgery is warranted whether cancer cells are found or not, surgery should be actively pursued for any lung mass that is clearly identified by CT. The current open-heart surgery is very safe, and the safety of surgery is 98%.