If you've received the news that your lung contains something "suspicious," this may be a source of great distress. The first thing that may come to mind is a dreaded word: cancer. In many cases, though, a lung nodule turns out to be benign. This means that it isn'tcancer. A hard part is waiting and not knowing. Here's information that may make your wait just a little bit easier.
What Are Benign Lung Nodules and Benign Lung Tumors?
A nodule is a "spot on the lung," seen on an X-ray or computed tomography (CT) scan. In fact, a nodule shows up on about one in every 500 chest X-rays. Normal lung tissue surrounds this small round or oval solid overgrowth of tissue. It may be a single or solitary pulmonary nodule. Or, you may have multiple nodules.
Your lung nodule is more likely to be benign if:
- You are younger than age 40.
- You are a nonsmoker.
- There is calcium in the nodule.
- The nodule is small.
A benign lung tumor is an abnormal growth of tissue that serves no purpose and is found not to be cancerous. Benign lung tumors may grow from many different structures in the lung.
What Are the Symptoms of Benign Lung Nodules and Tumors?
Benign lung nodules and tumors usually cause no symptoms. This is why they are almost always found accidentally on a chest X-ray or CT scan. However, they may lead to symptoms like these:
What Are the Causes of Benign Lung Nodules and Tumors?
The causes of benign lung tumors and nodules are poorly understood. But in general, they often result from problems like these:
Inflammation from infections such as:
- An infectious fungus (histoplasmosis, coccidioidomycosis, cryptococcosis, or aspergillosis, for example)
- Tuberculosis (TB)
- A lung abscess
- Round pneumonia (rare in adults)
Inflammation from noninfectious causes such as:
These are some of the more common types of benign lung tumors:
- Hamartomas are the most common type of benign lung tumor and the third most common cause of solitary pulmonary nodules. These firm marble-like tumors are made up of tissue from the lung's lining as well as tissue such as fat and cartilage. They are usually located in the periphery of the lung.
- Bronchial adenomas make up about half of all benign lung tumors. They are a diverse group of tumors that arise from mucous glands and ducts of the windpipe or large airways of the lung. A mucous gland adenoma is an example of a true benign bronchial adenoma.
- Rare neoplasms may include chondromas, fibromas, or lipomas -- benign tumors made up of connective tissue or fatty tissue.
How Are Benign Lung Nodules and Tumors Diagnosed?
How does your doctor know whether or not a lung nodule is benign? In addition to taking a history and doing a physical exam, your doctor may simply "watch" a nodule, taking repeated X-rays, over a period of two years or longer if the nodule is smaller than 6 millimeters and your risk is low. If the nodule remains the same size for at least two years, it is considered benign. That's because benign lung nodules grow slowly, if at all. On the other hand, cancerous nodules, on average, double in size every four months. Your doctor may continue to a check your lung nodule each year for up to five years to ensure that it is benign.
Benign nodules also tend to have smoother edges and have a more even color throughout as well as a more regular shape than cancerous nodules. In most cases, your doctor can check speed of growth, shape, and other characteristics such as calcification on a chest X-ray or CT scan.
It is possible that your doctor will order other tests, too, especially if the nodule changes in size, shape, or appearance. These may be done to rule out cancer or determine an underlying cause of the benign nodule. They may also help identify any complications. You could have one or more of these tests:
- Blood tests
- Tuberculin skin test to check for TB
- Positron emission tomography (PET) scan
- Single-photo emission CT (SPECT)
- Magnetic resonance imaging (in rare cases)
- Biopsy, tissue removal, and examination under a microscope to confirm whether the tumor is benign or cancerous
A biopsy can be done using a variety of methods such as aspirating cells through a needle or removing a sample of them using bronchoscopy. This procedure allows your doctor to look at your airway through a thin viewing instrument.
Treatment of Benign Lung Nodules and Tumors
In many cases, your doctor may simply observe a suspicious lung nodule with multiple chest X-rays over several years. However, your doctor may suggest a biopsy or removal of an entire nodule in situations like these:
- You are a smoker and the nodule is large.
- You have symptoms.
- A scan suggests the nodule might be cancerous.
- The nodule has grown.
A biopsy can often be done with small incisions and a short hospital stay. If your nodule is benign, you will not need any further treatment, except to manage any underlying problems or complications related to the nodule such as pneumonia or an obstruction.
If you need invasive surgery to remove a tumor, your doctor may recommend one or more tests beforehand to ensure your health. These will include blood tests, kidney, liver, and pulmonary (lung) function tests, and an ECG.
If needed, surgery may involve one of several procedures. Which surgery you have depends on the location and the type of your tumor or tumors. The surgeon may remove a small piece of tumor, one or more sections of a lobe, one or more lobes of the lung, or an entire lung. However, the surgeon will remove as little tissue as possible.