Pulmonary Nodule: Symptoms, Causes, Diagnosis and Treatment

Stain on the lung.

If you have been told that you have a pulmonary nodule or pulmonary nodules on an x-ray, you are probably terrified. What are some of the causes? How often do people have lung nodules? And what are the chances of lung cancer?

These are the most frequently asked questions that we would like you to answer immediately because, well, here, we will clear these and other doubts that may arise at any time.

It is essential to indicate that at least 60 percent of the lung nodules, in general, are not cancerous. We will discuss the possible causes, but it is equally essential to remember that if a nodule is lung cancer, there is still a good chance it can be cured.

A nodule, by definition, is less than three centimeters in diameter, and in this size, many lung cancers are very curable.

However, even for more significant lung cancers, the treatment and survival rates for lung cancer have improved significantly in recent years.

Currently, more ex-smokers and never smokers develop lung cancer than people who smoke.


What are pulmonary nodules?

A pulmonary nodule is defined as a “spot” in the lung three centimeters (about 1.5 inches) in diameter or less.

These nodules are often called “coin damage” when described in an imaging test. If an abnormality is seen on an x-ray of the lungs larger than three centimeters, it is considered a “lung mass” instead of a nodule and is more likely to be cancerous.

Pulmonary nodules usually need to be at least a centimeter in size before being seen on a chest x-ray, whereas sometimes, one or two-millimeter nodules can be seen on a CT scan.

Are they common?

Pulmonary nodules are pretty common and are found in one in 500 chest x-rays and one in 100 chest CT scans.

Approximately 150,000 lung nodules are detected in people in the United States each year. About half of people over 50 who smoke will have nodules on a chest CT scan.

If a potential nodule is seen on a chest x-ray, it is essential to have a CT scan. Small cancers can be missed on a chest x-ray.


Most pulmonary nodules do not cause any symptoms and are found “accidentally” or “incidentally” when a chest x-ray is performed for some other reason.

If there are symptoms, they may include coughing up blood, wheezing, shortness of breath, or respiratory infections if the nodule is located near a central airway.


Pulmonary nodules can be benign (non-cancerous) or malignant (cancer). The most common causes, in general, include granulomas (groups of inflamed tissue due to infection or inflammation) and hamartomas (benign lung tumors).

The most common cause of malignant lung nodules includes lung cancer or cancers of other body regions that have spread to the lungs (metastatic cancer).

The nodules can be divided into some primary categories:

Infections: infectious causes of nodules may include bacterial infections such as tuberculosis and other mycobacterial infections, fungal infections such as histoplasmosis, blastomycosis, aspergillosis, and coccidioidomycosis.

Also, parasitic infections such as ascariasis (intestinal worms), echinococcus (hydatid cysts), and paragonimus (liver flukes). When the immune system “blocks” the areas of infection, it often forms granulomas.

Inflammation: conditions such as rheumatoid arthritis, sarcoidosis, and Wegener’s granulomatosis, as well as pneumoconiosis such as silicosis, can also cause granulomas.

Benign tumors: benign lung tumors such as hamartomas (the most common benign lung tumor), bronchial adenomas, fibromas, blastomas, neurofibromas and hemangiomas. It may appear as a nodule in the lungs on an x-ray.

Malignant tumors: Cancers that may appear as nodules include lung cancer, lymphomas, sarcomas, and carcinoid tumors.

Metastasis: Pulmonary nodules may also be due to metastases from other cancers, such as breast cancer, colon cancer, bladder cancer, and prostate cancer.

Other benign nodules: pulmonary infarcts (areas of lung tissue that have lost their blood supply), abnormalities of the blood vessels (AV malformations), atelectasis (collapse of a part of the lung), pulmonary fibrosis, and amyloidosis are all other possible causes of a nodule pulmonary.


The first thing your doctor will want to do if you see a pulmonary nodule on your x-ray is to get any previous x-rays and compare them. More tests may not be necessary if the nodule or nodules have been present for a long time.

A new study may be required if the nodule is unknown or does not have previous X-rays to compare.

If a nodule is found on a chest x-ray, the first step will usually be to perform a CT scan of your chest. Other tests, such as an MRI, may be needed.

At this point, your doctor will want to know your history, as well as the risk factors you have for any pulmonary nodule. For example, if you traveled recently, you are more likely to have a fungal infection, while a malignant tumor may be more likely if you are a smoker.

The characteristics of the tumor will also be evaluated as seen on your computerized tomography.

A PET scan is sometimes helpful in defining a nodule. They are ” structural ” tests; unlike computed tomography and magnetic resonance imaging, they are “structural” tests. They can find lesions in the lungs, but they do not give a measure of what is happening in a nodule.

A small amount of radioactive sugar is injected into the bloodstream with a PET scan. Active growth tumors absorb more sugar that lights up in the test.

This can be useful to distinguish a growing tumor from scar tissue because an ever-increasing tumor will absorb more sugar. This is especially useful for those with previous lung infections or surgery that can cause scarring.

If a nodule does not appear to grow or has characteristics of a benign tumor (it has a “low probability” of being cancerous), sometimes a “wait and observe” approach with a repeated CT scan can be taken after a certain period.

Single solitary nodules that have remained unchanged for two or more years generally do not need any further study.

Lung nodule biopsy

Unfortunately, a lung biopsy is often needed to know what is causing a nodule. Fortunately, newer and less invasive tissue sampling methods are now usually available.

This can be important even if your doctor is sure of what is causing the nodule or nodules.

An example is when you think that nodules are metastatic cancer of another tumor, such as breast cancer.

Recent research suggests that even when a pulmonary nodule is found in a person expected to have lung metastases, only half of the nodules were metastases at the time of biopsy. Up to 25 percent, instead, was second primary lung cancer.

Depending on the nodule’s location, a fine needle biopsy may be performed. Sometimes, endobronchial ultrasound and a biopsy can be performed as part of a bronchoscopy.

Sometimes, an open biopsy may be necessary. Even when this is the case, newer techniques, such as video-assisted thoracoscopic surgery (VATS), can often be performed instead of a thoracotomy.

Benign vs. malignant nodules

In general, the probability that a lung nodule is a cancer is 40 percent, but the risk that a lung nodule is cancerous varies considerably based on several factors.

In people younger than 35 years, the possibility that a lung nodule is a cancer is less than one percent, while half of the lung nodules in people over 50 are malignant (cancerous).

Other factors that increase or decrease the risk of a lung nodule being cancer include:

Size: larger nodules are more likely to be cancerous than smaller ones.

Smoking: current and former smokers are more likely to have cancerous lung nodules than never smokers. We recommend investigating the percentage of smokers who get lung cancer.

Occupation: Some occupational exposures increase the likelihood that a nodule is a cancer.

Medical history: A history of cancer increases the chances of a nodule being malignant.

Family history: Those with nodules and a family history of lung cancer are more likely to have cancerous nodules than those with no family history.

Symptoms: The likelihood that a nodule is lung cancer is more significant if there are other signs or symptoms of lung cancer.

The nodule’s form/appearance: rounded and smooth nodules are more benign, while nodules “spiculated” or with irregular or lobular edges are more likely to be cancerous.

Solid / non-solid: solid nodules are more likely to be cancerous than non-solid nodules.

Growth: cancerous lung nodules tend to increase with an average doubling time of about four months, while benign nodules remain the same size over time.

Calcification: Calcified Pulmonary nodules are more likely to be benign.

Cavitation: The nodules described as “cavitary,” in which the inner part of the nodule appears darker on X-rays, are more likely to be benign.

Frosted glass nodules: nodules that are described as having a frosted glass appearance are often a challenge and can be benign or malignant. Due to this difficulty, a biopsy of these lesions is usually needed.

The number of nodules: those who have multiple nodules are more likely to have cancer than those who have a single solitary pulmonary nodule.

Location of nodules: lobules located in the right or left lower lobes or the right middle lobe of the lung are less likely to be cancerous than those in the left or right upper lobes.

Ethnicity and geographic location: A pulmonary nodule is more likely to be benign if you usually travel outside your country. For example, recent studies have found that pulmonary nodules due to schistosomiasis, a parasitic infection, are quite common in African migrants.

Similarly, nodules associated with fungal infections, such as coccidioidomycosis, are common in the Southwest.

Indeterminate pulmonary nodules

The number of lung nodules that radiologists read as “undetermined” has increased with the advent of lung cancer screening. Hearing that your nodule or nodules are indeterminate can be confusing. Is it not obvious?

Unfortunately, sometimes it is impossible, just in the imaging tests, to know if a nodule is malignant, even after considering all the above factors. To answer this question, a biopsy should be done.

Fortunately, radiologists, surgeons, and pathologists together are finding less invasive methods of tissue sampling. To better understand why this question is so tricky, you may need to obtain more information about the differences between benign and malignant tumors.

Detection of lung cancer

It has been discovered that the detection of lung cancer reduces the lung cancer mortality rate by 20 percent.

But as with any screening test, there is a risk of false positives, and it is common to find nodules on CT screenings.

But finding nodules does not always mean cancer. Studies estimate that only about five percent of the nodules found in a first lung CT scan are cancerous.


The treatment of pulmonary nodules varies widely depending on the cause, whether they are related to infections, inflammation, cancer, or other conditions.

The majority of benign pulmonary nodules, especially those present and have not changed over a few years, should not be a cause for concern.

If you have heard that you or a loved one has a pulmonary nodule, it is probably a combination of nerves and overwhelmed. There are so many different possibilities, and some of them are terrifying.

It may help to consider that most nodules are not cancerous, and even those that can be cured by surgery.

It is essential to keep in mind that science is changing rapidly. New diagnostic techniques are available, and new treatments are available every year.

Since medicine is changing so rapidly, it is essential to be an advocate in your medical care. If you do not get answers, ask more questions.

Consider getting a second opinion regardless of what you hear. Finally, contact family and friends. If your nodule turns out to be lung cancer, there is an active community of lung cancer that will receive it.