Children's Hospital Colorado

Congenital Pulmonary Airway Malformation (CPAM)

What is congenital pulmonary airway malformation?

Congenital pulmonary airway malformation (CPAM) is a relatively uncommon condition. It affects only 1 in approximately 4,000 babies born each year and involves lung lesions or masses that form in a baby's lower respiratory tract.

CPAM is the newer term for what was previously known as congenital cystic adenomatoid malformation (CCAM). It is part of a variety of conditions that involve cystic lung lesions or masses that form in the lower respiratory tract during a baby's development.

These are typically noncancerous masses that occur most commonly in one lung rather than both lungs, though any lobe of either lung may be affected.

As a parent, it can be overwhelming to discover your child has this condition. Fortunately, the Colorado Fetal Care Center has a large team of multidisciplinary fetal care specialists who are here for you from the initial diagnosis to continuing care after delivery.

What causes congenital pulmonary airway malformation?

The condition is found more commonly in males than females. It occurs because of an alteration in the lung development very early in pregnancy (about 8-9 weeks), though the exact cause is not known. It is not thought to be genetic, as no cases of recurrence of congenital pulmonary airway malformation in a sibling or offspring have been reported.

What are the risks of CPAM?

Depending on the size, the malformation can grow rapidly, causing a shift in structures within the chest (e.g., heart, lung, esophagus) which may not allow the baby to develop normally. In other cases, the mass may also compress the esophagus, causing amniotic fluid to increase, which puts the mother at risk for preterm labor.

The impact a malformation has on your baby will differ greatly depending on the size of the mass, its location and whether it impacts other organs in the chest cavity. Larger lesions can cause fetal hydrops (excessive fluid buildup) due to shifting in the chest and compression of the large vein (vena cava) that returns blood to the right side of the heart.

Maternal "mirror syndrome" can also develop in cases of fetal CPAM. In these cases, the mother accumulates excessive fluid similar to the fetus, as well as very high blood pressure (preeclampsia). Though quite rare, this condition would require immediate delivery.

The worst risk with congenital pulmonary airway malformation, however, is the immediate period of time before birth. If air becomes trapped within the cystic tumor, it can cause serious respiratory distress in the soon-to-be-born baby. After birth, ongoing cysts can result in recurrent bouts of pneumonia and other respiratory infections. Collapse of the lung (pneumothorax) is also an additional concern. In rare cases, some CPAM lesions can become cancerous.

What are the signs of CPAM?

In pregnancy, this mass is detected during an ultrasound examination, where it shows up as a bright area in the lung. It is generally a benign mass that will have no impact on the pregnancy itself. However, there are characteristics of the mass that could make it dangerous to a developing fetus and newborn, including the size of the mass and how cystic (dense) the mass is.

Depending on the type of malformation, the mass may appear similar to other conditions including diaphragmatic hernia, cystic hygroma or other cystic lesions. Because CPAM masses need to be differentiated from other lung masses and conditions, your baby should be evaluated with a detailed ultrasound and fetal MRI in order to determine the best next steps.

How is CPAM treated?

Because of the wide degree of severity of cysts and lesions associated with congenital pulmonary airway malformation, treatment plans vary just as widely. Depending on how the condition is impacting the baby, treatment options can range from surgery to specific support after delivery.

The Colorado Fetal Care Center is one of the most experienced and trusted fetal care centers when it comes to diagnosing and treating babies with congenital pulmonary airway malformation. Our state-of-the-art facility offers the best standards in treatments, as well as the best outcomes for babies diagnosed with congenital pulmonary airway malformation.

Congenital pulmonary airway malformation treatment, in general, includes monitoring, fetal intervention and surgery after birth:


After diagnosis, the fetus will be monitored with frequent ultrasounds to determine the growth of the mass and whether the mass is affecting surrounding organs. Other diagnostic tests might be ordered to rule out concurrent conditions. Often a detailed ultrasound of the fetal heart (fetal echocardiogram) is performed to assess the heart structures as well as how those structures are functioning.

Fetal intervention

Our team of fetal CPAM experts have extensively researched measurements and outcomes to determine indicators that predict which babies could potentially benefit from in utero treatment. During their research, they found that fetuses with CPAM, a dominant cyst and hydrops developed prior to 32 weeks may be candidates for treatment in utero.

Using ultrasound or other imaging methods to view the fetus and cyst, a thin tube (called a shunt) can be directly inserted into the cyst and left in place to drain the cyst into the amniotic fluid. This will cause the cyst to shrink and stop or decrease the accumulation of fluid in the fetus.

Some cases of CPAMs have multiple cysts that require fetus thoracoscopy to break up the cysts before the shunt can be placed. There is also a subset of patients who might benefit from open fetal surgery, whereby the CPAM is surgically removed from the fetal chest while still in the mother’s uterus.

Surgical treatment post-birth

Some cases of CPAM will regress spontaneously before birth, which is why monitoring mass growth is so important before deciding on surgical treatment. Careful postnatal evaluation is also important to ensure complete regression, however, if the mass is not removed before birth. Subtle abnormalities might be evident on a chest X-ray, but a chest CT or MRI may be necessary to detect residual CPAM tissue.

Complete resection of the CPAM mass, usually by the removal of the entire affected lung lobe (lobectomy), is the treatment of choice for CPAM if cysts or masses are still found after initial treatments.

What are the outcomes for CPAM surgery?

The long-term outcome for infants following CPAM surgery is excellent. Infants usually have remarkable growth of lung tissue that remains following surgery, which usually compensates for the portion of lung that was removed (if any).

Why choose the Colorado Fetal Care Center for your child's CPAM treatment?

If your child was diagnosed with congenital pulmonary airway malformation, you probably have a lot of questions. The Colorado Fetal Care Center can help answer them. Learn more about the Colorado Fetal Care Center, including our latest outcomes and the location of a fetal care center near you.

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