Solitary pulmonary nodule
Causes, incidence, and risk factors
More than half of all solitary pulmonary are noncancerous (benign). Benign nodules have many causes, including old scars and infections.
Infectious granulomas are the cause of most benign lesions.
You have a greater risk for developing a solitary pulmonary nodule if you have:
- Tuberculosis or been exposed to TB
- Infectious lung diseases caused by fungus, such as:
However, the above conditions makes it more likely that the solitary pulmonary nodule is noncancerous.
Young age, history of not smoking, calcium in the lesion, and small lesion size are factors associated with a noncancerous diagnosis.
Lung cancer is the most common cause of cancerous (malignant) pulmonary nodules.
There are usually no symptoms.
Signs and tests
A solitary pulmonary nodule is usually found on a chest x-ray. If x-rays repeated over time show the nodule size has remain unchanged for 2 years, it is generally considered benign.
A chest CT scan is often done to look at a solitary pulmonary nodule in more detail.
Other tests used to examine a solitary pulmonary nodule may include:
Ask your doctor about the risks of a biopsy versus monitoring the size of the nodule with regular x-rays.
Reasons for a biopsy or removing the nodule may include:
- The nodule size has grown compared to earlier x-rays
- A CT scan suggests the lesion is malignant (cancerous)
The outlook is generally good if the nodule is benign. If the nodule does not grow larger over a 2-year period, under most circumstances nothing more need be done. On occasion, the appearance of the nodule on CT scan may warrant continued follow-up.
Calling your health care provider
A solitary pulmonary nodule is usually found by your health care professional when a chest x-ray is performed for some other reason.
Cronin P, Dwamena BA, Kelly AM, Carlos RC. Solitary pulmonary nodules: meta-analytic comparison of cross-sectional imaging modalities for diagnosis of malignancy. Radiology. 2008 Mar;246(3):772-82.
Gould MK, Fletcher J, Iannettoni MD, et al. Evaluation of patients with pulmonary nodules: when is it lung cancer?: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:108S-130S.
Wahidi MM, Govert JA, Goudar RK, et al. Evidence for the treatment of patients with pulmonary nodules: when is it lung cancer?: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:94S-107S.
Reviewed By: Allen J. Blaivas, DO, Clinical Assistant Professor of Medicine UMDNJ-NJMS, Attending Physician in the Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Veteran Affairs, VA New Jersey Health Care System, East Orange, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.