Congenital Pulmonary Airway Malformations (CPAM)

What is a congenital pulmonary airway malformation?

Congenital pulmonary airway malformations, or CPAM, is a cystic lung disease that is congenital (present at birth). It happens when an abnormal mass forms in one of your baby’s lungs during pregnancy. The mass (often called a cyst or lesion) can make it harder for that lung to develop and work properly.

Doctors aren’t sure what causes some fetuses to develop CPAM. The condition is not hereditary (passed down in families). CPAM is rare and affects only about 1 in 25,000 pregnancies.

How is CPAM diagnosed?

CPAM is usually diagnosed during pregnancy when an abnormal mass shows up on a routine prenatal ultrasound. Other tests may be used to help with the diagnosis:

• MRI may be used to locate the lung lesion and figure out how big it is
• Fetal echocardiogram may also be used to check if your baby’s heart function is affected by the lesion

Your doctor will monitor your baby’s CPAM throughout your pregnancy and check to see if it is causing complications (secondary conditions) in you or your baby. Complications of CPAM include: 

• Hydrops, which is a very serious condition caused by fluid build-up around the baby’s heart. The fluid puts too much pressure on the heart and keeps it from pumping properly.
• Mirror syndrome, which can be an effect of hydrops. Mirror syndrome occurs when the mother’s body “mirrors” her baby’s condition. Hydrops in your baby can cause you to develop similar symptoms, like fluid retention (when the body holds too much water) and high blood pressure. Mirror syndrome is a rare but dangerous complication of CPAM that must be treated immediately.

How is CPAM treated during pregnancy? 

If your unborn baby is diagnosed with CPAM, a team of doctors will help you determine the best course of treatment. Many cases of CPAM won’t require treatment beyond close monitoring. If the CPAM gets dangerously large or is growing very quickly and your baby does need treatment, options include:

• Treatment with steroids to slow or stop the lesion’s growth.
• If there are large, fluid-filled cysts in your baby’s lungs, a doctor can drain them with a procedure called thoracentesis. During this procedure, a needle is inserted into the womb to draw the fluid out of the cyst and shrink it.
• Open fetal surgery to remove the lesion. This treatment option is for fetuses that have developed severe hydrops. Usually babies that undergo fetal surgery must be delivered by C-section,.
• Early delivery may be recommended if the mother has developed mirror syndrome, which is a life-threatening condition. Early delivery is avoided until the baby’s CPAM poses a risk to the mother’s life.

How is CPAM treated in newborns? 

Babies with CPAM are at a higher risk of developing complications during and after birth, and should be delivered at a hospital with a NICU (neonatal intensive care unit). After delivery, treatment for babies with CPAM depends on the size and severity of the lesion:

• Some newborns may have trouble breathing during or after delivery because of their CPAM. To treat these complications, doctors may use a ventilator to help the baby breathe.
• Newborns with very large lesions may need to have surgery immediately after birth to remove the CPAM and prevent breathing problems.
• In some cases, the CPAM can be removed at birth with a surgery called the EXIT procedure. The EXIT procedure is similar to a C-section, and occurs while the mother is asleep under anesthesia. An incision (surgical cut) will be made to partially deliver your baby out of the uterus. This is different from a regular C-section, where the baby would be fully delivered out of the uterus. In the EXIT procedure, the baby is left attached to your placenta (the organ that provides your baby with oxygen and nutrients) while the doctor operates on the affected lung and removes the CPAM. The baby is fully delivered after the CPAM is removed.
• Newborns with small lesions may still need to have the abnormal lung tissue removed. If the CPAM is not causing any breathing problems, the baby can go home after delivery. If surgery is needed to remove the lesion, the procedure will be scheduled before the baby’s first birthday.