Pulmonary (Lung) Nodules

Two doctors looking at lung scans

What is a lung nodule? An abnormal growth that forms in a lung, a pulmonary nodule may not cause any symptoms, especially if it is relatively small. Many lung nodules go undetected until they are discovered during an imaging test performed for an unrelated reason.

I have a lung nodule. Now what?

Pulmonary nodules are common, most are benign and many do not require treatment. This may lead many people to wonder what causes lung nodules—and when to worry about lung nodules.

Lung nodule symptoms

If nodules in the lungs are large enough to press on an airway, symptoms may occur, such as:

  • Coughing
  • Wheezing
  • Shortness of breath

Additionally, if a lung nodule is cancerous, it may cause:

  • Vocal hoarseness
  • Hemoptysis (coughing up blood)
  • Recurrent respiratory infections
  • Chest pain
  • Fatigue
  • Loss of appetite
  • Unexplained weight loss

Lung nodule causes

A lung nodule is rarely a sign of lung cancer. Instead, it is usually a result of inflammation caused by a past illness, infection or injury. What causes lung nodules? When lung tissue becomes inflamed, a small clump of cells (granuloma) may accumulate. Over time, a granuloma can calcify and form a noncancerous lung nodule.

Other possible causes of lung nodules include:

  • A respiratory infection, such as pneumonia, COVID-19 or tuberculosis
  • Exposure to airborne lung irritants or pollutants
  • An autoimmune disease, such as rheumatoid arthritis or sarcoidosis
  • Histoplasmosis, an infection caused by inhaling fungal spores 
  • Scar tissue in the lungs

Although anyone can develop pulmonary nodules, the risk is higher among current and former smokers as well as people who are older than 65, have a family history of cancer or have been exposed to radon, asbestos or secondhand smoke.

How are lung nodules diagnosed?

If an imaging test reveals a solitary pulmonary nodule, a physician may suggest an active surveillance program. Usually, this involves a CT scan every six to 12 months. If a nodule does not grow during a two-year surveillance period, it is unlikely to be cancerous. Can lung nodules disappear? In some cases, yes.

To further evaluate a lung nodule that is more than 12 millimeters in diameter, a physician may order a:

  • Bronchoscopy. A physician guides a thin tube (bronchoscope) down the patient’s throat and into the lung, then uses a special surgical instrument attached to the end to retrieve a tissue sample from the nodule for analysis under a microscope.
  • CT scan-guided biopsy. To retrieve a tissue sample from a nodule on the outer part of a lung, a physician inserts a thin needle using real-time CT images for guidance.
  • Positron emission tomography (PET) scan. A safe radioactive chemical is injected before images are captured; the chemical will help illuminate any cancerous cells in the resulting images.

Pulmonary nodule treatment

When evaluating treatment options, a physician will refer to a lung nodule size chart. Usually, a small, noncancerous lung nodule will not require treatment, although an antibiotic or antifungal medication may be prescribed to address an underlying infection. A surgical procedure such as video-assisted thoracic surgery (VATS) or a thoracotomy may be considered to remove a nodule that is growing, causing symptoms or cancerous.

If you have been diagnosed with a pulmonary nodule and would like to be screened for lung cancer, contact Moffitt Cancer Center to request an appointment with an experienced pulmonologist in our Thoracic Oncology Program by calling 1-888-663-3488 or completing our new patient registration form online. A referral is not required. When you turn to Moffitt, you will be a top priority of a cancer center that delivers nationally ranked care in new and transformative ways.


American Cancer Society: Lung Nodules