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Lung Disease & Respiratory Health Center

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Benign Lung Tumors and Nodules

What Are the Causes of Benign Lung Nodules and Tumors? continued...

Birth defects such as a lung cyst or other lung malformation.

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, shorter 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, CT or PET 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:

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.

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