What is CPAM?

CPAM (congenital pulmonary airway malformation) is an abnormal mass of lung tissue, normally affecting one lung lobe. The CPAM can be macrocystic, meaning it is made up of one or more large cysts, or microcystic, meaning it is made up of many smaller cysts. The CPAM is part of the lungs and connected to the lung’s blood supply. 

CPAM is the most common type of congenital lung malformation (CLM). Congenital means a condition that is present at birth and a lung malformation means that part of the lungs did not develop properly. 

What is BPS?

BPS (bronchopulmonary sequestration) is the second most common congenital lung malformation after CPAM. Like CPAM, a BPS is an abnormal growth of lung tissue, but unlike CPAM, the mass is not connected to the lung’s blood supply.

A sequestration means something that is separate. In the case of BPS, it is the blood supply that is separate from the pulmonary (lung) system, and there is no communication with the airway. The BPS is connected instead to a nearby systemic vessel, normally the aorta. 

A BPS can be intralobar (meaning the mass is within or part of a lung lobe, but with a separate blood supply) or extralobar (meaning the mass is not part of the lung structure at all).

Is CPAM or BPS cancer?

No. CPAM and BPS are not cancers. The masses are benign: they are not cancerous. There is thought to be a very small risk of cancer, but research is needed to determine whether it’s because the malformations may become cancer in the future if not removed, or whether a childhood lung cancer (called pleuropulmonary blastoma or PPB) is misdiagnosed as CPAM or BPS. 

How do you know if it’s CPAM or BPS?

The radiologists and surgeons will be able to give a guess based on the CT. However, the only way to know for sure is for the mass to be studied by a pathologist after it is removed during surgery. A number of these malformations may be a mix of two types of lesions. All of these lesions (CPAM, BPS, bronchial atresia, lobar emphysema) are treated the same way.

Can a mass be both CPAM and BPS?

Yes. A mass can show characteristics of both CPAM (a cystic mass of non-functioning lung tissue) and BPS (with a blood supply coming from outside the lungs). These are called hybrid lesions. Again, the only way to know the exact characteristics of the lung mass is when a pathologist looks at it after surgery.

Are there other types of CLM?

Bronchogenic cysts, CLE (congenital lobar emphysema), and bronchial atresia are rarer types of congenital lung malformations. 

Is CCAM something different?

No. CCAM is just the old term for CPAM.

How are CPAM and BPS diagnosed?

Nowadays most congenital lung malformations like CPAM and BPS are diagnosed during pregnancy at a routine 20 week ultrasound scan. The CPAM or BPS mass appears much brighter than healthy lung tissue on an ultrasound up until around 28 weeks. Imaging technology is getting better and better at detecting lung abnormalities more accurately and earlier than ever before. Previously, CPAM or BPS would never be detected (especially if the mass caused no problems) or only be discovered incidentally, normally following an X-ray or other imaging study after repeated chest infections. 

How common is CPAM or BPS?

Nobody knows exactly, but being diagnosed with a congenital lung malformation is still uncommon, even with technological advances leading to much better detection rates. Congenital lung malformations altogether are thought to impact 1 in 2,500 live births. 

What is the prognosis for someone born with a congenital lung malformation?

The prognosis is excellent. In the overwhelming majority of cases a CPAM or BPS will not affect a child’s life expectancy or quality of life. In some rarer cases, the CPAM or BPS presents more serious complications during the pregnancy or immediately after birth. In particular, if the lung mass grows very quickly or is very large fluid can build up in nearby organs. This build up of fluid is a rare but very serious condition called hydrops. When the CPAM or BPS is more dangerous, the pregnancy must be extremely carefully monitored by specialists. 

Will the baby be able to breathe at birth?

In the majority (90%) of cases, babies with a congenital lung malformation are asymptomatic at birth, meaning they breathe normally without needing oxygen, and act like other babies. In other cases a baby may be symptomatic, meaning they need some help or breathing support early on.

What is the treatment for CPAM or BPS?

Treatment differs by where in the world the patient is receiving medical care. In the US, most cases are nowadays spotted during pregnancy. In these situations, the standard practice is to monitor the size of CPAM or BPS during the pregnancy to make sure the mass is not growing too big or affecting the baby's other organs. The baby will then have surgery to remove the CPAM or BPS when they are at least a few months old, although in some cases surgery has to happen sooner. 

In other parts of the world (like Europe and Australia) the CPAM or BPS will still be monitored closely during pregnancy, but doctors follow more of a “wait and see” approach and don’t always recommend surgery for every patient.  

What causes CPAM or BPS?

Nobody knows for sure but CPAM or BPS is not caused by anything the mother did, or didn’t do, during pregnancy.