Benign Lung Tumors

A lung tumor is an abnormal rate of cell division or cell death in lung tissue or in the airways that lead to the lungs. Types of benign lung tumors include hamartomas, adenomas and papillomas. In almost all cases, benign lung tumors require no treatment, but your doctor will probably monitor your tumor for changes.


What are benign lung tumors?

Hearing the word “tumor” naturally may cause fear. However, “tumor” simply means an abnormal buildup of tissue that occurs when cells divide too quickly or do not die off as they normally should. A lung tumor is a tumor that occurs in the lung tissue itself or in the airways that lead to the lungs. Lung tumors can be either cancerous (malignant) or benign (non-cancerous).

If you’ve been told that you have a lung tumor and it “looks like it’s benign,” what does that mean? Should you still be concerned?

Compared to malignant tumors, benign lung tumors:

  • Aren’t cancerous, so won’t spread to other parts of the body.
  • Grow slowly, or might even stop growing or shrink.
  • Aren’t usually life-threatening.
  • Usually do not need to be removed.
  • Can expand and push against nearby tissues but will not invade, destroy, or replace other tissues.

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Are there different types of benign lung tumors?

Yes, there are several types of benign lung tumors. Tumors that are generally larger than three centimeters (1.2 inches) are called masses. If your tumor is three centimeters or less in diameter, it’s commonly called a nodule. If the nodule forms in your lungs, it’s called a pulmonary nodule.

Types of benign lung tumors and nodules include:


Hamartomas are the most common type of benign lung nodule. They account for about 55% of all benign lung tumors, and 8% of all lung tumors. About 80% are found in the outer portion of the lung's connective tissue. The rest are found inside the bronchial tubes (the airways leading to the lungs).

Hamartomas are made up of "normal" tissues such as cartilage, connective tissue, fat, and muscle but in abnormal amounts. They are usually less than four centimeters in diameter and appear in chest X-rays as a coin-like round growth. In about 15% of cases they may look like fluffy wool or popcorn. Hamartomas usually stay within a limited area and are not likely to press against nearby tissue. They are found more often in males than females, and between the ages of 50 and 70.

Bronchial adenomas

Adenomas are another common type of benign lung nodule. They grow in the large airways of the lungs (bronchi) and in the mucus glans or ducts of the windpipe.


Papillomas are a less common type of benign lung tumor. They grow in the bronchial tubes, sticking out from the surface area where they attached. Papillomas are divided into three types.

  • Squamous: One or more squamous papillomas can occur in both children and adults. They result from infection by the human papilloma virus (HPV), the same virus that causes warts and certain sexually transmitted infections.
  • Glandular: These papillomas are less common than squamous papillomas and develop in larger airways compared with squamous papillomas. They occur in all ages but mostly adults. They almost always appear as one nodule, centrally located. No cause has been identified.
  • Mixed squamous and glandular: These papillomas contain a mix of squamous and glandular papilloma tissue. Only a small number of cases have been reported. These papillomas have the potential to eventually turn cancerous because the squamous cells can change over time.

Other benign lung tumors

Other rare tumors include chondromas, fibromas, neurofibromas and lipomas. These tumors are made up of connective tissue or fatty tissue.

How common are benign lung nodules?

Pulmonary nodules are fairly common. They are seen in about one of every 500 chest X-rays and in about one out of every 100 chest CT scans. At least 60% of pulmonary nodules seen on chest X-rays turn out to be benign, and 99% of those on chest CT are benign. About half the people who smoke and are over age 50 will have nodules on a CT scan of their chest.


Symptoms and Causes

What causes benign lung nodules?

There are many possible causes of benign lung tumors and nodules. These include:

  • Granulomas (small clumps of inflamed cells) that develop as a result of a bacterial infection such as tuberculosis or from fungal infections such as histoplasmosis or coccidiomycosis.
  • A lung abscess (pus-filled infection usually caused by bacteria).
  • Inflammation from such diseases as rheumatoid arthritis, sarcoidosis or Wegener’s granulomatosis.
  • Infection from human papilloma virus.
  • Birth defects such as a lung cyst, scars, or other lung malformation.
  • No known cause.

What are the symptoms of benign lung tumors?

You may not have any symptoms. More than 90% of nodules are found by accident, when you get a chest X-ray or CT (computed tomography) scan for some other reason.

If you do have symptoms, they may include:

  • Mild cough that lasts for a long time.
  • Shortness of breath, difficulty breathing, wheezing.
  • Coughing up blood.
  • Rattling sounds in the lungs.

Diagnosis and Tests

How are benign lung nodules diagnosed?

Lung tumors and nodules can be seen on a chest X-ray or CT (computed tomography) scan. Often, the nodules are found accidently when you have a chest scan for something else.

Your healthcare provider may want to perform a bronchoscopy to take a closer look at the mass and get a tissue sample (biopsy). During a bronchoscopy, a scope with a built-in camera is slid down your throat and into your lungs while you are sedated. Other ways to gather a tissue sample are by inserting a needle into the mass, guided by a CT-scan, to extract a small amount of tissue, or through a surgical incision.

Additional information your healthcare team uses to make the diagnosis include:

  • Size of the nodule: Your healthcare provider may chart the rate of growth of your nodule. The smaller the nodule, the more likely it is to be benign. Also, benign nodules grow very slowly, if at all, while cancerous nodules on average can double in size every four months or less.
  • Nodule content, shape and color: Another way to tell a benign lung nodule from a malignant one is to test its calcium content. Benign nodules have higher calcium content and are normally smoother and more regularly shaped. Benign nodules have a more even color pattern than malignant nodules. Malignant nodules more commonly have irregular shapes, rougher surfaces, and color variations or speckled patterns.

Management and Treatment

How are benign lung tumors treated?

In most cases, benign lung tumors don’t require treatment. Your healthcare provider will want to take a series of X-rays or CT (computed tomography) scans over a period of months to years to watch for any changes in tumor size or features.

Your healthcare team may recommend a biopsy or surgery to remove the tumor if:

  • You are a smoker or have a high risk of cancer.
  • You have difficulty breathing or other troubling symptoms.
  • Tests show that cancer could be present.
  • The nodule continues to grow.

Outlook / Prognosis

What can I expected if I have been diagnosed with a benign lung tumor?

If you and your healthcare provider have agreed to simply monitor your lung tumor, you will want to make sure you don’t miss any follow up appointments. If you’ve had surgery to remove a benign lung tumor and the tumor has been completely removed, you usually will not need any additional treatment.

When should I call my doctor?

Call your healthcare provider if:

  • You experience a change or increase in cough or cough up blood
  • Develop new shortness of breath, fever, chills or chest pain.
  • Have an unplanned weight loss of 10 or more pounds.

A note from Cleveland Clinic

The commonly called “spot on the lung” is what doctors call a nodule. Feel reassured that most small nodules are benign and are not lung cancer. Even in the worst case scenario – the nodule does turn out to be lung cancer – it’s likely to be at an early stage and very treatable. Because most small nodules don’t cause noticeable symptoms, your healthcare provider will want to keep a close eye on it over the next couple of years with X-rays or CT scans to make sure it’s not growing or changing.

It’s certainly normal to be anxious even if there’s the smallest chance that you may have lung cancer. Always know that you can call your healthcare team with any of your concerns or questions. The one thing you can do for yourself – if you smoke, quit. Your healthcare team can help you quit too.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 07/15/2020.

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