What Are Congenital Lung Malformations?

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Congenital lung malformations are a rare problem that causes parts of the lung and airways to not form normally during prenatal development. Depending on the severity, this might cause significant symptoms or no problems at all.

These also sometimes are called “congenital thoracic malformations.” They are rare conditions, estimated to affect 1 in 10,000 infants born. Some estimates put the number closer to 1 in 3,000, based on new information from sensitive prenatal scans.

Making diagnosis a team task
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Types of Congenital Lung Malformation

The terminology around congenital lung malformations is still in flux, and some conditions are known by more than one name.

One of the more common types is CPAM (congenital pulmonary airway malformation (CPAM). It is also known as congenital cystic adenoid malformation (CCAM). Some of the other types described are:

  • Pulmonary sequestration
  • Congenital lobar emphysema (infantile lobar hyperinflation)
  • Arteriovenous malformation in the lungs
  • Bronchogenic cysts (or other cyst types)
  • Congenital small lung
  • Agenesis of the lung (absent lung)
  • Bronchial atresia (absent bronchus)

Lung Malformation Symptoms

The symptoms of a congenital lung disease might first appear at any age. For example, some infants with a more severe kind of congenital lung disease might show signs of respiratory distress, and they may look like they are having trouble breathing. Other symptoms might exist, like wheezing, blue skin, and difficulty feeding.

A fetus with a very severe kind of congenital lung malformation might show signs of hydrops fetalis on ultrasound. This is an extremely serious condition in which abnormal amounts of fluid buildup in one or more organs. If the overall problem is very severe, an affected infant might die shortly after birth.

But sometimes these are minor issues that don’t cause any symptoms at all. The abnormality might only be detected because of an imaging test, perhaps on a prenatal ultrasound or a chest X-ray done in childhood or adulthood. Some such malformations are probably never identified, or only if a person has an autopsy after their death.

There is a lot of variation in the severity and type of symptoms experienced by someone with a congenital lung malformation. Symptoms can vary based on the amount of the respiratory tract involved, the type of malformation, and the specific location of the affected regions. Some potential problems include:

  • Cough (potentially bloody)
  • Recurrent lung infections
  • Hemothorax
  • Pneumothorax
  • Blue-tinged skin (cyanosis)
  • Fatigue
  • Shortness of breath
  • Clubbing of the fingers
  • Heart failure (uncommon)

Congenital lung malformations also seem to increase the risk of getting certain types of cancer that affect the lung, including bronchoalveolar carcinoma, rhabdomyosarcoma, and adenocarcinoma. However, this is highly debated among experts.

It’s not at all clear how much this risk is increased, or whether it is increased more for certain types of congenital lung malformations. It’s also not clear that removal of the affected region totally eliminates this risk.

Rarely, people with congenital lung disease also have congenital issues that affect other organs, such as the heart or parts of the nervous system.

Being Aware of Potential Complications

If you know you have a congenital lung malformation, see your doctor promptly for potential signs of complications, like a bloody cough or a fever with chest pain. You might need treatment of the complication and perhaps surgical removal of the affected area. For a life-threatening problem, like sudden difficulty breathing, call 911. 

Causes

The development of the lungs and airways takes place through a complex series of steps during prenatal development. The cells that will become the airways leading down to the lungs and the lungs themselves form in very complicated and coordinated steps. When something interferes with this developmental process, a congenital malformation of the lung can result.

Your lung contains very small pockets within it, called alveoli. This is where oxygen you’ve breathed in from the air enters the blood. Excess carbon dioxide from the blood enters the alveoli and leaves the body as you breathe out. That’s critical, because all cells of your body need oxygen to live, and carbon dioxide can cause problems if it isn’t removed normally.

When the lungs don’t develop normally, it can lead to symptoms and complications. Most importantly, if not enough of the lung can perform its normal function, it’s a life-threatening situation. Fortunately, for many people with congenital lung malformations, enough of the lung is working normally, so the problems aren’t as significant.

Certain genes have been identified that may be involved in causing congenital lung malformations, but a lot of the details on this are still not clear. These abnormalities don’t seem to run in families.

Exposure to certain environmental factors may also play a role. For example, we know that factors such as infection during pregnancy and exposure to certain drugs and chemicals can broadly increase the risk of congenital abnormalities in various organ systems.

However, we still don’t understand much about the issues that might increase the risk of congenital lung malformations. Most of the time, there is no identifiable cause.

Diagnosis

Congenital lung malformations can be diagnosed at any age, including prenatally. This condition is being diagnosed more frequently than in the past, probably because of increases in imaging (both prior to and after birth).

For some perfectly healthy adults, a chest X-ray done for some other reason might be the first they learn that they have a congenital lung malformation.

Medical history and exam provide the important foundations for diagnosis. The healthcare provider asks about recent symptoms and any long-term medical conditions, as well as family medical history. The exam gives important clues about whether the person needs immediate treatment.

It’s important to distinguish other medical problems that might have similar symptoms or imaging findings (like from a lung infection, sarcoidosis, or certain genetic syndromes.) That’s important, because not all these possibilities have the same treatment. It’s also important to see if there are issues with any other organ systems of the body, like the heart.

Medical imaging tests also play a key role. Increasingly, congenital lung malformations are being diagnosed during pregnancy, from detailed anatomic ultrasound scans commonly performed around week 20. If a potential issue is found, a series of ultrasounds can provide information about whether the problem might be going away or worsening.

Tests like fetal echocardiogram may be able to give a sense of whether other organs might be involved as well.

Chest X-ray provides a helpful initial diagnostic tool. However, it’s important to note that chest X-ray does not pick up all kinds of congenital lung malformations. Computerized tomography (CT) of the chest is generally considered the gold standard for diagnosis, as it provides more detailed information than a simple X-ray.

Other imaging tests might be used as well, depending on the circumstances. This might include CT angiography or magnetic resonance imaging (MRI). Bronchoscopy—which lets doctors look inside the pathways of the airways—can also be helpful in some situations.

Basic tests may also be necessary to rule out other causes and get a sense of how severe the problem is, depending on the context. For example, this might include

Treatment

For a fetus diagnosed prenatally, treatment inside the womb isn’t recommended unless the affected area still seems to be getting larger by the last 10 weeks of pregnancy. Additionally, it might be considered for a fetus with signs of hydrops fetalis.

In this situation, treatment options are limited and come with significant risks. However, some options might be thoracocentesis or a pleuro-amniotic shunt (to drain off the fluid around the lungs).

Another approach is sclerotherapy, which might help to clot off some of the blood vessels to the area. In some cases, prenatal steroids given to the mother may be of benefit. Open surgery during pregnancy is a last resort option.

Some infants diagnosed with congenital lung malformations might need stabilizing treatment at birth, if they show signs that their lungs aren’t working well enough. For example, this might include supplementary oxygen or respiratory support on a ventilator or through extracorporeal membrane oxygenation (ECMO).

Surgery

The definitive treatment is surgery, which might be performed soon after birth, several months later, or in later childhood or adulthood. Surgery is usually recommended if a person is experiencing symptoms from their congenital lung malformation, like repeated infections.

Most types of surgery remove the affected area and part of the surrounding tissue. Fortunately, for most people with congenital lung malformations, this leaves enough functioning lung tissue. Depending on the context, more or less of the lung might need to be removed.

For example, a wedge resection removes only a small portion of the lung. In a lobectomy, the surgeon removes a larger section, a lung lobe (one of the three of the right lung or one of two on the left). The most invasive approach is a pneumonectomy, which involves removing an entire lung.

Often it is possible to use a minimally invasive type of surgery, such as video-assisted thoracoscopic surgery (VATS). Such approaches can use smaller incisions compared to an open surgery.

When There Aren’t Symptoms

Most infants who have been diagnosed with potential congenital lung malformations are born without complications and don’t have any symptoms at birth. And some older people are first diagnosed later, like from an imaging study, but don’t have any symptoms.

Medical professionals haven’t agreed on the best way to treat such individuals. On the one hand, surgery can prevent complications from congenital lung malformation, such as a pneumothorax, repeated infections, or a malignancy. On the other hand, surgery itself always poses risks like infection or blood clots (though those may be relatively uncommon).

It is tricky, because we don’t have a good handle on how high the risks of these complications of a congenital lung malformation really are. That is particularly true when we consider that different types of congenital lung malformations may have different risks.

In some cases, it might be better to wait and see if a complication develops, and then proceed with surgery. But it may be reasonable to get a surgery proactively, to help prevent future problems.

There often isn’t one right answer when deciding whether you or your loved one should preventively have a surgery for a congenital lung malformation. Ask your doctor about the specifics of your type of malformation and what that means for your risk—at surgery and in terms of potential future complications. It is also reasonable to get a second medical opinion. Through talking with your healthcare team, you’ll decide what makes sense for you.

If it is decided not to surgically remove a congenital lung malformation, many practitioners recommend repeated imaging scans, to monitor for potential development of a cancer.

A Word From Verywell

Congenital lung malformations are an uncommon medical problem, but one that can be particularly frightening for expectant parents. Fortunately, most of these babies will do very well, and people are there to provide support and treatment if needed. Work with your medical team to figure out a management plan that makes sense for your family. 

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