Solitary pulmonary nodule
Lung cancer - solitary nodule; Infectious granuloma - pulmonary nodule; SPNA solitary pulmonary nodule is a round or oval spot (lesion) in the lung that is seen with a chest x-ray or CT scan.
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Causes
More than half of all solitary pulmonary nodules are noncancerous (benign). Benign nodules have many causes, including scars and past infections.
Infectious granulomas (which are formed by cells as a reaction to a past infection) cause most benign nodules. Common infections that often result in granulomas or other healed scars include:
- Tuberculosis (TB) or exposure to TB
- Fungal infections, such as aspergillosis, coccidioidomycosis, cryptococcosis, or histoplasmosis
Primary lung cancer is the most common cause of cancerous (malignant) pulmonary nodules. This is cancer that starts in the lung.
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Symptoms
A solitary pulmonary nodule itself rarely causes symptoms.
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Exams and Tests
A solitary pulmonary nodule is most often found on a chest x-ray or chest CT scan. These imaging tests are often done for other symptoms or reasons. It may also be found by a lung cancer screening chest CT most often done for people age 50 to 80 years who have a 20 pack-year smoking history.
Your health care provider must decide whether the nodule in your lung is most likely benign or of concern. A nodule is more likely benign if:
- The nodule is small, has a smooth border, and has a solid and even appearance on an x-ray or CT scan.
- You are young and never smoked.
Your provider may then choose to monitor the nodule over time by repeating a series of x-rays or CT scans.
- Repeat chest x-rays or chest CT scans are the most common way to monitor the nodule. Sometimes, lung PET scans may be done.
- If repeated x-rays show that the nodule size has not changed in 2 years, it is most likely benign and a biopsy is not needed.
Your provider may recommend a biopsy of the nodule to check for cancer if:
- You are a smoker.
- You have other symptoms of lung cancer.
- The nodule has grown in size or has changed when compared to earlier images.
- The nodule has features that make it more likely to be cancerous (malignant).
A lung needle biopsy may be done by placing a needle directly through the wall of your chest, or during procedures called bronchoscopy or mediastinoscopy.
Tests to check for TB and other infections may also be done.
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Treatment
Ask your provider about the risks of having a biopsy versus monitoring the size of the nodule with regular x-rays or CT scans. Treatment may be based on the results of the biopsy or other tests.
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Outlook (Prognosis)
The outlook is usually good if the nodule is benign. If the nodule does not grow larger over a 2-year period, often nothing more needs to be done.
References
Bueno J, Landeras L, Chung JH. Updated Fleischner Society guidelines for managing incidental pulmonary nodules: common questions and challenging scenarios. Radiographics. 2018;38(5):1337-1350. PMID: 30207935 pubmed.ncbi.nlm.nih.gov/30207935/.
Jokerst CE, Gotway MB. Thoracic radiology: noninvasive diagnostic imaging. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 20.
Tanner NT, Gould M, Slatore CG. Pulmonary nodule. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 41.