Health Information

A solitary pulmonary nodule is a round or oval spot (lesion) in the lungs that is seen with a chest x-ray or CT scan.

More than half of all solitary pulmonary nodules are benign (not cancerous). Benign nodules have many causes, including old scars and infections.

Infectious granulomas (inflammation of granular tissue) are the cause of most benign lesions. When a nodule is malignant, lung cancer is the most common cause. Exposure to tuberculosis or an infectious fungus (histoplasmosis, coccidioidomycosis, cryptococcosis, and aspergillosis) can increase the risk of developing a solitary pulmonary nodule, but also makes it more likely that the nodule is benign.

Young age, absence of tobacco exposure, calcium in the lesion, and small lesion size are factors favoring a benign diagnosis.

There are usually no symptoms.

A solitary pulmonary nodule is usually found on a chest x-ray. If serial chest x-rays (repeated x-rays over time) show the nodule size unchanged for 2 years, it is considered benign. A chest CT scan is often performed to evaluate a solitary pulmonary nodule in detail.

Other tests may include the following:

• PET scan
• Percutaneous needle biopsy
• Single-photon emission CT (SPECT)
• Skin tests to rule out infectious causes
• Surgical lung biopsy

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:

• Smoking
• 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, nothing more should be done.

The nodule could be due to a malignancy, including lung cancer.

A solitary pulmonary nodule is usually found by your health care professional when a chest x-ray is performed for some other reason.

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.