What is Congenital Pulmonary Airway Malformation (CPAM)?

From the Guidelines

CPAM stands for Congenital Pulmonary Airway Malformation, a rare birth defect affecting the lungs, where abnormal lung tissue develops during fetal growth. Management of CPAM depends on the severity and symptoms:

• For asymptomatic cases: Observation with regular follow-up imaging.
• For symptomatic or large lesions: Surgical resection is recommended, typically performed between 3-6 months of age. Specific management steps:

1. Prenatal diagnosis: Usually detected on routine ultrasound 1.
2. Fetal monitoring: Regular ultrasounds to assess growth and potential complications.
3. Postnatal evaluation: Chest X-ray and CT scan to confirm diagnosis and assess extent.
4. Treatment decision: Based on symptoms and size of the lesion.
5. Surgery: Lobectomy or segmentectomy to remove affected tissue.
6. Post-operative care: Pain management, respiratory support if needed. CPAM occurs due to arrested lung development between 4-7 weeks of gestation. Early intervention is crucial to prevent complications such as recurrent infections, pneumothorax, or rarely, malignant transformation. Long-term prognosis is generally good after successful treatment. According to the Society for Maternal-Fetal Medicine (SMFM) clinical guideline #7, for fetal CPAM, macrocystic type: fetal needle drainage of effusion or placement of thoracoamniotic shunt; microcystic type: maternal administration of corticosteroids, betamethasone 12.5 mg IM q24 h 2 doses or dexamethasone 6.25 mg IM q12 h 4 doses 1. It is also noted that hydrops occurs in only about 5% of fetuses with CPAM but confers a poor prognosis without treatment 1.

From the Research

Definition and Prevalence of Congenital Pulmonary Airway Malformation (CPAM)

• Congenital pulmonary airway malformations (CPAMs) represent a cluster of rare lung malformations affecting 1 in 2500 live births 2.
• CPAMs include cystic and non-cystic lung lesions, accounting for about 30-40% of developmental lung bud anomaly lesions 3.

Characteristics and Natural History of CPAM

• The natural history of many CPAMs is to increase their size in the second trimester, reach a plateau, and, in about 50% of cases, regress and become barely detectable during the third trimester 2.
• CPAMs vary in their histological features, epidemiological and clinical presentation, severity, and prognosis, supporting the embryologic hypothesis of arrested lung growth during branching morphogenesis 3.

Diagnosis and Management of CPAM

• CPAMs can be diagnosed prenatally using fetal ultrasound, and serial assessment of these lesions throughout pregnancy is common 4.
• Management of CPAM is controversial, especially for asymptomatic patients, and may involve surgical resection or a conservative approach 5.
• Surgical resection is the standard of therapy for symptomatic CPAMs, while the management of asymptomatic cases remains controversial 3.
• A multidisciplinary team including gynecologists, neonatologists, radiologists, pediatricians, and pediatric surgeons is recommended in pre, postnatal management and in the postsurgical follow-up of all children with CPAMs 3.