A solitary pulmonary nodule (SPN) is spot on the lung four centimeters or less surrounded by normal lung tissue. Many are not malignant. Depending on the population studied, 50-85% of are benign.
Strong evidence of a benign SPN includes the following:
- The presence of a dense central, laminated, or popcorn calcification on routine chest radiograph.
- Old chest radiograph showing the lesion present but unchanged over the last two years.
- Having a patient less than 30 years of age who is a nonsmoker.
In evaluating a patient with an SPN, it is our practice to find any old chest x-rays that could have been done previously. It is important for us to look at the actual film and not just rely on a radiology report. In our patients who are smokers, we are always worried about malignancy, and bronchoscopy is often undertaken to rule out tumors in the bronchial tubes that sometimes cannot be seen on chest x-rays. Often biopsies are required. These can be achieved at the time of bronchoscopy, or are often done by radiologists in a CT scanner with direct computer guidance. Sometimes, biopsies are not needed, and patients can undergo serial examinations with chest x-rays or CT scans to watch for growth in the lung nodule. Lesions followed over a two year period that do not change on chest imaging are benign lesions approximately 99% of the time. This often provides great reassurance to both physician and patient.