Congenital Lung Malformations

Congenital Lung Malformations

Congenital lung malformations are a family of structural developmental abnormalities of the lung that arise from an error in the embryologic development of the lung. The lung normally develops from one kind of tissue that becomes the airways arising originally from the upper digestive system, and another kind of tissue that becomes the blood vessels and connective tissue of the lung. These two kinds of tissue must "communicate" clearly with each other to form a normal lung. Errors in communication can lead to one or more of these malformations.

Many lung malformations are diagnosed on routine prenatal high-resolution ultrasound. Lung malformations can be seen as early as 15-20 weeks gestation and are usually incidental findings. On rare occasion, particularly if the malformation is quite large, they can cause the fetus to look very swollen (fetal hydrops). This is a worrisome finding. Almost always, the only action needed if a lung malformation is identified is prenatal consultation with a pediatric surgeon comfortable and familiar with these types of diagnoses. These lung malformations are usually isolated findings, not genetic in origin, and not part of a syndrome.

Only those malformations large enough to cause symptoms will be diagnosed after birth because a well appearing child would have no reason to be evaluated any further. Newborn infants who are symptomatic from a large malformation will demonstrate hydrops (see above), heart failure, or respiratory failure. Older children can present with an infection in the malformation that looks like a lung abscess (bronchogenic cyst) or repeated pneumonia in the same location (pulmonary sequestration or CCAM).

In either case, the diagnostic evaluation is derived from a combination of chest X-rays, computerized axial tomography (CAT) scan (usually with intravenous contrast agents), or magnetic resonance imaging (MRI). Pulmonary function testing and echocardiography may compliment the evaluation.