What Is a Lung Nodule? Everything to Know

Medically Reviewed By Thomas Johnson, PA-C
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Lung nodules are round growths on your lungs that are typically less than 10 millimeters (mm). Most nodules do not cause symptoms. Your doctor may find a lung nodule during a routine CT scan or chest X-ray. While most lung nodules are noncancerous, your doctor may request a biopsy to confirm the type of nodule.

Read on to find out more about lung nodules. This guide includes information about symptoms, causes, treatments, and more.

What are the symptoms of a lung nodule?

A person is getting a CT scan.
PER Images/Stocksy United (person appearing is a model and used for illustrative purposes only)

Lung nodules can be so small that you may not experience any symptoms. Most nodules are less than 10 mm. Routine screening finds more than 90% of all lung nodules. 

If you do experience symptoms, they may resemble the common cold. Symptoms can include:

A lung nodule larger than 30 mm is called a mass. Cancerous masses may cause more prominent respiratory symptoms.

Noncancerous lung nodules are more likely to grow slowly or not at all. A larger lung nodule may indicate cancer.

Lung nodules that have an irregular shape or border could be cancerous. Your lung nodule is more likely to be noncancerous if it is smooth and round.

Noncancerous nodules tend to occur on the lower lobes of your lungs. In contrast, cancerous nodules tend to be more predominant in the upper lobes.

What causes a lung nodule?

There are different causes of cancerous and noncancerous lung nodules.

Cancerous lung nodules

A major cause of cancerous lung nodules is primary or secondary lung cancer. Primary cancer begins in the lungs, while secondary cancer spreads to the lungs from elsewhere in the body.

Carcinogen exposure is a risk factor for developing cancerous lung nodules. For example, smoking may be a major cause. About 50% of people over age 50 who smoke will have lung nodules.

Other risk factors for cancerous lung nodules include being over age 50 and having a history of cancer. People younger than 35 do not usually develop cancerous lung nodules. 

Learn more about lung cancer.

Infection

Infection can cause noncancerous lung nodules. A prior tuberculosis or fungal infection may cause a lung nodule to form. Histoplasmosis and coccidioidomycosis (valley fever) are two fungal infections that can cause a lung nodule.

Learn more about infections.

Inflammation

Rheumatoid arthritis and sarcoidosis are two conditions that can cause inflammation in your body. Some of these conditions can run in families. If a relative has a history of lung nodules, you may be more likely to develop them. 

Learn more about inflammation.

What are the treatments for a lung nodule?

Treatments for a lung nodule will depend on whether or not it is cancerous.

Monitoring

If your lung nodule is noncancerous and small, your doctor may only recommend monitoring it. You may require follow-up scans to ensure your nodule has not grown significantly. If your nodule has remained unchanged for 2 years, you may not require further follow-up appointments. Talk with your doctor about routine monitoring for benign, long lasting lung nodules.

Surgery

If your doctor suspects that your lung nodule is cancerous, they may recommend surgery to remove it. Early removal can help prevent it from spreading to other areas of your body.

A video-assisted thoracic surgery is a minimally invasive treatment option. It involves a surgeon inserting a small camera to see your lungs without requiring a large incision. Robotic-assisted thoracic surgery involves your surgeon using robotic instruments and a small camera to remove the tissue. 

Thoracotomy and mini-thoracotomy are more invasive than robotic-assisted or video-assisted surgery. During a mini-thoracotomy, your doctor removes the cancerous nodule through an incision in your chest.

Wedge resection and segmentectomy procedures remove the portion of the lung where a nodule occurs. A segmentectomy removes the entire lobe where the nodule occurs. In contrast, a wedge resection removes a smaller wedge of lung tissue. Both surgeries are more invasive than a mini-thoracotomy because they remove more than just the nodule.

Your doctor will explain which treatments they recommend and answer any questions you may have.

Learn about lung cancer surgery.

When should I see a doctor?

Fewer than 5% of all lung nodules are cancerous. However, you should contact your doctor if you have any respiratory symptoms. Your healthcare team may perform a biopsy on the tissue to determine if your lung nodule is cancerous. 

You should make an appointment with your doctor for the following symptoms:

If you experience new respiratory symptoms but don’t have a common cold, contact your doctor. 

When should I worry about a lung nodule?

Seek medical care for a lung nodule if you develop respiratory symptoms or worry it may be cancerous.

Most lung nodules are found during a CT scan or X-ray for another condition. Your doctor can discuss whether or not they suspect the nodule is cancerous.

How do doctors diagnose a lung nodule?

If a lung nodule doesn’t cause symptoms, your doctor may only find it during a routine imaging exam. Your doctor is most likely to identify a lung nodule with a CT scan.

If you have respiratory symptoms, your doctor may want to rule out infection first. They will likely ask about your symptoms and perform a physical exam. The exam may include listening to your lungs and checking your oxygen levels. 

A chest X-ray or CT scan will show the size, location, and shape of your nodule. If your doctor suspects a cancerous lung nodule, they may recommend follow-up testing. A PET scan will give your doctor a better image of the nodule. 

Your doctor may also request a biopsy of the lung nodule. During this procedure, they obtain a tissue sample to have examined for cancerous cells. Learn more about biopsy procedures.

What are the complications of a lung nodule?

Most complications from noncancerous lung nodules result from invasive treatment and testing procedures. Surgical complications include:

  • hemorrhage
  • pulmonary embolism
  • pleural effusion
  • infection

The main complication of cancerous lung nodules is the spread of cancer. 

Contact your doctor if you have concerns about the complications of lung nodules and possible treatments.

Summary

Lung nodules are round mounds of tissue in your lungs. Lung nodules can be cancerous or noncancerous.

Noncancerous lung nodules are slow growing, small, and usually do not cause notable symptoms. Cancerous lung nodules are irregularly shaped and tend to grow faster. Noncancerous nodules typically appear in the lower lung. In contrast, cancerous nodules are more common in the upper lung. You may experience respiratory symptoms, such as wheezing or coughing.

Cancerous lung nodules occur at a higher rate in people who smoke. Noncancerous nodules typically result from an infection.

Your doctor can help identify your lung nodules through a CT scan or X-ray. If they suspect a noncancerous lung nodule, they will routinely monitor its growth over the next 2 years. If the nodule is cancerous, they may recommend surgery to remove it.

Most lung nodules are noncancerous. However, routine imaging is important to help catch any potential nodules early. 

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Medical Reviewer: Thomas Johnson, PA-C
Last Review Date: 2022 Sep 28
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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