Lung nodules may be cancerous, but most are not, according to Mayo Clinic. They range from about 0.2 inch to a bit more than 1 inch in size.
Lung nodules are common masses in the lung and show on X-rays as white, round shadows, explains Mayo Clinic. Any nodule that is larger than 1.2 inches has a higher chance of being cancerous. If there is a nodule on the lung, a doctor looks for changes over time, so most people must get an X-ray every year. If it doesn't change within two years, it is likely not cancerous.
Lung nodules that are not cancerous usually develop due to previous infections, and they typically require no treatment, claims Mayo Clinic. A doctor may recommend regular X-rays to track any change, and if a change occurs, further tests may be necessary to determine if the condition is cancerous. Some of the tests that might occur include bronchoscopy, tissue biopsy, positron emission tomography scans or a CT scan.
Though benign lung nodules mean cancer is not present, they still may cause signs, states WebMD. These signs include wheezing, coughing, fever and shortness of breath. Most, however, do not cause symptoms, and doctors find them accidentally when doing X-rays on the lungs for other reasons.