Yes, a lung nodule can be cancerous. But most lung nodules aren't cancerous.

Lung nodules are small clumps of cells in the lungs. They're very common. Most lung nodules are scar tissue from past lung infections.

Lung nodules usually don't cause symptoms. They're often found by accident on a chest X-ray or CT scan done for some other reason.

If a lung nodule is small and it isn't growing, it's not likely to be cancer. It probably doesn't need treatment. Your health care provider may look at past imaging tests to see if the nodule is new or changed. You might need periodic CT scans to see if the nodule grows.

Providers may be more worried about larger lung nodules and those that grow over time.

If your nodule is large or is growing, you might need more tests to see if it's cancer. This might include imaging tests, such as CT and positron emission tomography (PET) scans. Another test might be a procedure called a biopsy. This involves removing a piece of the nodule for testing in a lab.