Please note: This information was current at the time of publication. But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit, the AAFP patient education website.

Information from Your Family Doctor

Lung Nodules


Am Fam Physician. 2015 Dec 15;92(12):online.

  See related article on pulmonary nodule

What is a lung nodule?

A lung nodule (NA-jule) is a small, ball-shaped mass that can grow in the lung. It can range in size from smaller than a pea to the size of a golf ball or larger. Your doctor can see it on a chest x-ray or CT scan. Most of the time, there are no symptoms.

Does a lung nodule mean I have cancer?

Most nodules are benign (be-NINE), which means not cancer. Infectious granulomas (gran-yoo-LO-mas) are the most common cause of benign nodules. Granulomas are formed when a group of immune cells in your body tries to fight an infection. A lung nodule can also be malignant (mah-LIG-nant), which means it is cancer or may turn into cancer. Patients who smoke or have smoked in the past, who are older than 40 years, and who have other types of cancers are at higher risk of getting lung cancer.

What tests will my doctor do?

Your doctor will usually look at x-rays and CT scans of your chest to check a lung nodule. He or she may also review old x-rays or CT scans to see if the nodule is old or new, or has changed over time. If more information is needed, your doctor may also do another type of scan called a PET scan.

What if my doctor thinks the nodule is benign?

Your doctor may watch the nodule over time with several CT scans. The scans may be done three, six, or 12 months apart to make sure the nodule is not growing.

What if my doctor thinks the nodule is malignant or growing?

Your doctor may send you to a lung or cancer specialist if your nodule is growing or if it may be malignant. The specialist might do a biopsy, which is when a doctor takes out a small piece of lung tissue and examines it under a microscope to see if it is cancer.

Where can I get more information?

Your doctor

National Library of Medicine

This handout is provided to you by your family doctor and the American Academy of Family Physicians. Other health-related information is available from the AAFP online at

This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.


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