What are the types of congenital pulmonary malformations, including Congenital Pulmonary Airway Malformations (CPAM), bronchogenic cysts, Congenital Lobar Emphysema (CLE), and pulmonary sequestrations?

Types of Congenital Pulmonary Malformations

Congenital pulmonary malformations comprise four main types: Congenital Pulmonary Airway Malformations (CPAM), bronchopulmonary sequestrations, Congenital Lobar Emphysema (CLE), and bronchogenic cysts. 1, 2, 3

Primary Classification System

The major categories of congenital lung malformations include:

• Congenital Pulmonary Airway Malformation (CPAM) - previously termed congenital cystic adenomatoid malformation (CCAM), represents developmental anomalies of the airway with cystic or solid components that can be macrocystic or microcystic 4, 2, 3

• Bronchopulmonary Sequestration - abnormal lung tissue that lacks normal bronchial communication and receives its blood supply from systemic arteries rather than pulmonary circulation, occurring as either intralobar or extralobar variants 1, 2, 3

• Congenital Lobar Emphysema (CLE) - characterized by hyperinflation of one or more pulmonary lobes due to air trapping, most commonly affecting the left upper lobe 1, 2, 5

• Bronchogenic Cyst - fluid-filled cystic structures arising from abnormal budding of the primitive foregut, which can be located within the lung parenchyma or mediastinum 1, 2, 5

• Bronchial Atresia - isolated congenital obstruction of a bronchus with distal mucus accumulation and hyperinflation 6, 3

Clinical Presentation Patterns

Symptomatic Presentation

• Space-occupying lesions cause early postnatal respiratory distress requiring immediate surgical intervention 1
• Mediastinal shift from large CPAM or effusions impairs venous return and cardiac output, potentially leading to hydrops fetalis 4
• Esophageal compression from thoracic masses results in polyhydramnios 4

Asymptomatic Detection

• Increasing frequency of prenatal diagnosis via antenatal ultrasonography, with confirmation by chest CT angiography in the first months of life 6, 3
• Incidental findings in childhood or adult life during imaging for unrelated conditions 6

Diagnostic Approach

Chest CT angiography is the definitive imaging modality for confirming the diagnosis and characterizing the specific type of congenital lung malformation. 5, 3

• Prenatal ultrasound identifies lesions as abnormal air, air/fluid, or fluid-filled cysts 5
• Postnatal CT provides detailed anatomical characterization including vascular supply patterns critical for distinguishing sequestrations 5, 3
• Echocardiography evaluates for associated cardiac anomalies and hemodynamic effects 4

Management Algorithm

For Symptomatic Lesions

• Immediate surgical resection is indicated for all symptomatic congenital lung malformations causing respiratory distress or complications. 1, 6
• Surgical approach includes segmentectomy or lobectomy for intrapulmonary lesions and simple excision for extralobar sequestrations and bronchogenic cysts 5
• Thoracoscopic or open thoracotomy techniques are both acceptable with low complication rates 5, 3

For Asymptomatic Lesions

• Early elective surgery is generally recommended to prevent respiratory and infectious complications, though this remains subject to debate. 1, 6
• Resection minimizes risk of recurrent infections, pneumothorax, and potential malignant transformation associated with CPAM, bronchopulmonary sequestration, and bronchogenic cysts 3
• Asymptomatic CLE may not require resection and can be managed expectantly 5
• Alternative approach involves expectant management with planned follow-up, though the true incidence of adverse outcomes including malignancy remains unknown 3

Special Considerations

Fetal Intervention

• Macrocystic CPAM can be treated with needle drainage or shunt placement 4
• Microcystic (predominantly solid) lesions may respond to corticosteroid therapy as first-line treatment 4
• Large bronchopulmonary sequestrations have been treated with laser ablation of the feeding vessel 4

Malignancy Risk

• CPAM, bronchopulmonary sequestration, and bronchogenic cysts carry an associated but poorly quantified risk of malignant transformation 3
• KRAS somatic mutations have been confirmed in CPAM tissue, suggesting genetic susceptibility to tumor development 3

Common Pitfalls

• Failing to obtain CT angiography for definitive characterization leads to inadequate surgical planning 5, 3
• Assuming all asymptomatic lesions can be safely observed without considering individual malignancy risk 3
• Inadequate long-term follow-up and transition to adult care for patients managed conservatively 3