As the standard of living and concern for one’s health improves, more and more people are opting for regular health checkups. Chest photos or CT exams are an essential part of a health checkup. If a mass or “shadow” in the lung is found after a physical examination, people can feel great fear. Despite the modern medical advances, people still talk about “cancer”, do I have lung cancer? What should I do next? Do I need surgery and what is the effect of surgery? How long do I have? In fact, the masses or “shadows” found in the lungs are not always lung cancer, but may be tuberculosis or inflammation. So, how do we diagnose the nature of the lesion found? Generally speaking, as a physician, we will first screen for inflammation and tuberculosis. After a short period of regular anti-infection treatment (usually about 2 weeks), lesions that do not change significantly or no longer change after partial reduction should be alerted to lung cancer and other lung tumors. As far as thoracic surgery is concerned, what can we do for this group of friends? First, for diagnosed lung cancer, surgery is preferred if the lesion can be removed. For those patients who do not have or cannot get evidence of tumor, surgical lesion biopsy is an effective method. Although there are some patients whose pathological findings after surgery confirm that they are not tumors but inflammatory pseudotumors or tuberculosis spheres, these lesions cannot be completely cured by drugs and may develop scar carcinoma, which should be removed surgically. Traditional thoracic surgery requires a large incision in the chest and most patients have a great fear of it. Nowadays, minimally invasive thoracoscopic surgery can be done through 3-4 small 1-2cm holes under the surveillance of TV thoracoscope. Since thoracoscopic surgery does not require a large open chest incision and does not brace the ribs, patients experience significantly less pain after surgery and fewer post-surgical complications. In conclusion, the masses or “shadows” found in the lungs are not terrible, and most patients will have satisfactory results if they choose timely diagnosis and treatment.