Solitary Pulmonary Nodule

Solitary Pulmonary Nodule

Solitary pulmonary nodules are round or oval lesions found on the lungs that can be seen with a chest x-ray, computed tomography (CT) scan, or positron emission tomography (PET) scan. The majority of solitary pulmonary nodules are noncancerous. Previous scarring from injury or infection may cause such nodules, which rarely present with symptoms. Infectious granulomas, or reactions to prior infections such as tuberculosis, aspergillosis, coccidioidomycosis, cryptococcosis, and histoplasmosis lead to most cases of benign solitary pulmonary nodules. If the nodule is small, has smooth borders, and has a solid, even appearance on imaging studies, and the patient is a nonsmoker, the nodule is more likely to be benign. Imaging studies may be used to monitor any changes, or a biopsy can be performed if the nodule changes or if the patient is at risk for lung cancer.

Biopsy tissue samples can be taken for examination under a microscope to confirm or rule out the presence of cancer cells. A lung needle biopsy goes through the chest wall, a bronchoscopy uses a tube to go through the airway to the lung, or a mediastinoscopy sends a lighted instrument through a small neck incision to reach the mediastinum, the space in the chest between the lungs.

Different medical advisory boards recommend different methods of follow up, but recent guidelines focus on avoiding unnecessary radiation in patients with low or no smoking history or other risk factors with nodules smaller than 4 mm.

Solitary Pulmonary Nodule

Most malignant solitary pulmonary nodules occur in patients at risk for or with existing lung cancer. A 2013 study in Annals of Nuclear Medicine suggested that combined PET/CT scans were more sensitive in differentiating benign from malignant pulmonary lesions, but acknowledged the PET test does run the risk of a false positive – suggesting cancer when none is present. CT scans remain important in identifying nodule features that might suggest malignancy or confirm other signs of benign disease. Following the nodule over time can help determine if it grows too slowly or quickly to likely be malignant. The doubling time of most malignant solitary pulmonary nodules is 1-6 months.

Surgical removal of a malignant solitary pulmonary nodule may be performed by thoracotomy (open lung surgery) or VATS (video-assisted thorascopic surgery). Successful treatment rates are similar to other types of lung cancer; intervening early and removing tumors before they spread gives a patient the best chance for a good long-term outcome.

To see an x-ray of a solitary pulmonary nodule, visit the National Library of Medicine’s MedlinePlus image.

Find support groups, studies, ways to quit smoking, research and access to clinical trials for lung cancer at the American Lung Association.