A number of conditions can cause scar tissue in the lungs, and while some are progressive, others cause a limited amount of scarring to develop. Some people diagnosed with lung cancer develop scar tissue after the tumors are removed and healed. Other progressive diseases, such as pulmonary fibrosis, continue to form scars around vital parts of the lung tissue.
When an individual undergoes radiation therapy for lung cancer, tumors in the lungs are bombarded with radiation designed to kill the tumor. In doing so, however, you can also damage nearby blood vessels and air sacs. As these areas heal, scar tissue often forms. When the radiation is stopped and the tumor is removed, scar tissue will stop forming.
Other conditions result in the formation of scar tissue that progressively worsens. Pulmonary fibrosis, also known as interstitial pneumonitis, occurs when the tissues of the lungs swell and begin to form scar tissue around the alveoli. This can be caused by repeated exposure of the individual to microscopic substances that cause tiny holes in the tissues of the lungs. The body responds by patching up the holes, and with continued exposure and the buildup of scar tissue, the lungs can lose some of the elasticity that allows them to expand and contract with each breath.
Many people who develop pulmonary fibrosis get it through their jobs. Inhalation of chemicals, asbestos, minerals, or even some types of mold can scar the lungs. This is also one of the most avoidable scarring conditions, as much of the exposure can be limited by proper equipment and masks. A condition called chemical pneumonia can develop with prolonged exposure to toxins that cause inflammation and irritation in the lung tissue. One of the ways the body combats this intrusion is by forming scar tissue.
Damage to the lungs, from an accident or physical injury or from surgery done for another condition, can also cause scarring. Persistent inflammation or the presence of tumors can cause irritation in the lungs, which in turn results in fluid buildup along their surfaces. When this fluid is drained, scars can form where the procedure was done. External trauma to the lungs, such as a puncture or smoke inhalation, can also be responsible for the buildup of scar tissue as a healing process. In some cases, bacteria that enter the body in another area can settle in the lungs and damage the tissues there, causing the body to develop scar tissue to heal the wounds.