Congenital Pulmonary Airway Malformation (CPAM) is a rare, non-cancerous lung condition that forms during fetal development. This anomaly involves an abnormal mass of lung tissue that does not function as healthy lung tissue. It is a condition present at birth, affecting approximately 1 in 4,000 to 1 in 35,000 live births.
What is Congenital Pulmonary Airway Malformation?
Congenital Pulmonary Airway Malformation (CPAM), previously known as congenital cystic adenomatoid malformation (CCAM), refers to an abnormal growth of lung tissue during early fetal development, between 5 and 17 weeks of gestation. This mass, typically located in one lung, does not function like normal lung tissue and can be solid, cystic, or a mix of both. The exact cause of CPAM is unknown, and it is generally not considered genetic or linked to maternal factors.
CPAMs are categorized into five types based on their microscopic features and cyst size. Type 0, the rarest, involves very small cysts and is incompatible with life due to severe impairment of gas exchange. Type I is the most common, characterized by one or more large cysts and often presents with respiratory distress in newborns. Type II features multiple smaller cysts and is frequently associated with other congenital anomalies. Type III appears as a bulky, firm mass with microcysts and can involve an entire lung lobe, potentially leading to respiratory distress at birth.
How CPAM is Detected
CPAM is frequently detected during routine prenatal ultrasound scans, often around the 20-week mark. These scans allow doctors to observe the presence, size, and location of the abnormal lung mass, which may appear as a bright spot in the fetal chest. Fetal Magnetic Resonance Imaging (MRI) can provide more detailed information about the lesion’s characteristics and its impact on developing lung tissue.
If CPAM is not identified before birth, postnatal detection may occur if a baby develops symptoms. Chest X-rays can reveal lesions, and larger ones may show a shift in the mediastinum (the space between the lungs). A Computed Tomography (CT) scan or MRI is recommended after birth to further define the lesion’s size, location, and characteristics, even if initial X-rays appear normal.
Signs and Symptoms of CPAM
Many babies diagnosed with CPAM prenatally remain asymptomatic after birth. However, symptom presentation varies widely depending on the lesion’s size and location. When symptoms do occur, they are often related to respiratory distress.
Newborns might exhibit rapid breathing (tachypnea), grunting sounds, or retractions, which are visible pulling in of the skin between the ribs or at the neck during breathing. A blue tint to the skin, lips, or gums (cyanosis) can also be present, indicating inadequate oxygenation. Feeding difficulties and recurrent lung infections, such as pneumonia, are additional signs that may prompt investigation for CPAM.
Treatment Options for CPAM
The management of CPAM varies, with surgical resection being the primary treatment for most cases. For asymptomatic or smaller lesions detected prenatally, a watchful waiting approach is adopted, involving close monitoring of the lesion’s size during pregnancy through serial ultrasounds. Many CPAMs may decrease in size or disappear on imaging before birth.
If the lesion is significant or causes symptoms after birth, surgical removal of the affected lung lobe (lobectomy) is the standard procedure. This surgery is performed within the first few months of life, typically between 3 to 6 months of age, to prevent complications like recurrent infections or, in rare instances, malignant transformation. Minimally invasive techniques, such as thoracoscopic surgery, are increasingly used, involving smaller incisions and leading to a shorter hospital stay. In rare, severe cases causing life-threatening complications like fetal heart failure (hydrops) before birth, prenatal interventions may be considered.
Outlook and Long-Term Care
The prognosis for babies diagnosed with CPAM is favorable, particularly with timely intervention. Most children achieve excellent outcomes following surgical removal of the malformation. The remaining healthy lung tissue undergoes compensatory growth, which helps to maintain normal lung function.
Long-term follow-up care is recommended to monitor for any potential complications. This care includes regular check-ups with a pediatrician and sometimes imaging studies like chest X-rays or CT scans, though the frequency and necessity of imaging can vary. Children who have undergone CPAM treatment lead normal, healthy lives and can participate in various activities without significant long-term respiratory issues.