A 2-week-old female came to clinic for her health maintenance examination. She was a term infant who had been diagnosed with a congenital pulmonary airway malformation on pre-natal ultrasound in the right chest. The lesion had decreased in size on the last ultrasound before delivery. She was delivered vaginally and had had no problems at delivery, in the hospital or since going home. The pediatric surgeon had seen the patient and wanted to followup in 3 months if the patient remained asymptomatic. Her parents continued to monitor her closely and described “funny breathing” where she will breath slightly more rapidly and then have a short period of not breathing. They do not report labored breathing, and she never has problems with color changes, difficulty feeding or abnormal sounds while breathing.
The pertinent physical exam revealed a 3.980 kg infant with weight gain of 22 grams/day since her last visit. HEENT was normal as was her lung exam. During the examination the parents pointed out the “funny breathing” which was normal periodic breathing.
The diagnosis of an asymptomatic newborn with a prenatally diagnosed congenital pulmonary airway malformation was made. The pediatrician reassured the family about the periodic breathing and reviewed symptoms of respiratory distress and encouraged them to call if she had any problems also with feeding. The patient’s clinical course at her 1-month and 2-month visit showed that she was growing well and continued to be asymptomatic.
Figure 128 – AP view of the chest taken on the first day of life shows hazy increased density in the inferior and lateral aspect of the right lung, most probably due to the presence of multiple small cysts in the right lower lobe. The findings were felt to be compatible with a congenital pulmonary airway malformation.
Congenital lung malformations (CLM) are commonly identified with prenatal ultrasound and occur in ~1:2400 live births. The natural history shows that lesions may remain the same, enlarge or appear to disappear. There is a wide-range of clinical manifestations. Patients may be asymptomatic or symptomatic at birth and often develop symptoms later.
The overall natural history is difficult to ascertain as there are fewer studies done in older children and adults. Those that are done often lack a good denominator by which to judge the incidence or prevalence. Resection is carried out usually if a patient is symptomatic, but in patients who are asymptomatic the decision can be more difficult. Timing of resection for asymptomatic patients is debated and usually occurs between 6 month – 2 years and try to spare as much tissue as necessary. Main reasons for early treatment of CLMs is the potential for continued or compensatory lung development and growth. Alveolar units continue to develop until age 2 and there can be increased size of existing alveoli before and after this age. Within the alveoli there are changes that can occur up to age 4-5 years. Other studies show many children becoming asymptomatic but again there are complicating issues with these studies.
Common types of CLMs include:
- Bronchogenic cysts
- Lesions arise from the bronchial tree usually around the mediastinum, lined with respiratory epithelium that are mucus-filled, may have a component of cartilage
- Lesions are single or multicystic
- Usually resected
- Bronchopulmonary sequestration (BPS)
- Lesion is pulmonary tissue that does not connect to the tracheobronchial tree and whose arterial blood supply is systemic (not pulmonary)
- Can be located extra-lobar or intra-lobar
- Can also be a hybrid lesion with CPAM (see below)
- Usually resected
- Congenital pulmonary airway malformation (CPAM) – 1 in 10,000 live births
- Lesions are multicystic, of various sizes and locations
- They can be unilobar, bilobar, multifocal and even bilateral
- Can also be a hybrid lesion with BPS
- Usually resected
- Congenital lobar emphysema (CLE)
- Pulmonary lobe(s) are overdistended as it is thought that there is a localized catilaginous deficiency which causes local bronchomalacia and overdistention
- Airway collapse with expiration can cause air trapping distally leading to overdistention
- Often resected but depending on the lesion they may be followed conservatively
CLM outcome is correlated primarily to lesion size. Patients may have outcomes from intra-natal fetal death to being asymptomatic for long periods of time.
Potential problems and complications of CLMs include:
- Fetal demise
- *Respiratory problems – tachypnea, oxygen requirement, respiratory collapse
- *Lesion expansion – mass effect and/or loss of pulmonary tissue
- *Infection – pneumonia, cyst infection
- *Malignancy – confused with a primary malignancy (i.e. pleuropulmonary blastoma (extremely rare and seen almost exclusively in young children, bronchioalveolar carcinomas) or potential transformation to a malignancy
- Cardiac issues – due to mass effect or in BPS high output cardiac failure can occur if a large arterial blood vessel serves it
- Spontaneous pneumothorax
- Resection problems – chest wall deformities, scoliosis, nerve damage, scarring problems
* issues commonly cited as reasons for resection
Questions for Further Discussion
1. What is in the differential diagnosis of respiratory distress? A review can be found here
2. What causes respiratory failure? A review can be found here
3. What are indications for pediatric surgery referral?
- Disease: Congenital Pulmonary Airway Malformation | Birth Defects
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Boucherat O, Jeannotte L, Hadchouel A, Delacourt C, Benachi A. Pathomechanisms of Congenital Cystic Lung Diseases: Focus on Congenital Cystic Adenomatoid Malformation and Pleuropulmonary Blastoma. Paediatric Respiratory Reviews. 2016;19:62-68. doi:10.1016/j.prrv.2015.11.011
Hall NJ, Stanton MP. Long-term outcomes of congenital lung malformations – Semin Pediatr Surg. 2017 Oct;26(5):311-316. Accessed October 6, 2020. https://pubmed.ncbi.nlm.nih.gov/29110827/
Leblanc C, Baron M, Desselas E, et al. Congenital pulmonary airway malformations: state-of-the-art review for pediatrician’s use. European Journal of Pediatrics. 2017;176(12):1559-1571. doi:10.1007/s00431-017-3032-7
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa