Congenital Cystic Diseases of the Lung
Pulmonary sequestration, bronchogenic cyst, CCAM, and congenital lobar emphysema — embryology to surgery.
Overview
Congenital cystic lung diseases are characterised by aberrant differentiation of bronchi, bronchioles, alveoli, and pulmonary vasculature during embryogenesis. All forms can cause neonatal respiratory distress. With increasing use of antenatal imaging, many are now detected in utero. The major forms are: pulmonary sequestration, bronchogenic cyst, congenital cystic adenomatoid malformation (CCAM/CPAM), and congenital lobar emphysema (CLE).
Pulmonary sequestration
Aberrant, non-functional, dysplastic lung tissue lacking normal tracheobronchial communication, supplied by a systemic artery (usually the aorta). Two types: intralobar (ILS) and extralobar (ELS).
| Feature | Intralobar (ILS) | Extralobar (ELS) |
|---|---|---|
| Proportion | 75% | 25% |
| Sex | M = F | M > F |
| Location | Within normal lung (no separate pleura) | Outside normal lung (own visceral pleura) |
| Venous drainage | Pulmonary veins (90%) | Systemic (IVC or azygos) |
| Most common lobe | LLL > RLL | Left posterior costophrenic angle |
| Associated anomalies | Rare | Common (diaphragmatic hernia, cardiac) |
| Presentation | Recurrent pneumonia / haemoptysis in child or young adult | Asymptomatic mass in infant |
Diagnosis: CT angiography or MRI demonstrates the aberrant systemic artery — essential pre-operative mapping to prevent catastrophic haemorrhage during resection. Antenatal detection by Doppler ultrasound at 16–24 weeks is possible.
Always identify and ligate the aberrant systemic artery (aortic branch) before dividing the pulmonary parenchyma. Failure to do so results in retraction of the vessel into the abdomen and life-threatening haemorrhage. For ILS, lobectomy is standard. For ELS, simple excision of the sequestered tissue with ligation of its feeding artery.
Bronchogenic cyst
Arise from abnormal budding of the foregut during the embryonic period. Most are mediastinal (70–85%); intrapulmonary cysts are less common. Lined by respiratory epithelium and contain mucoid fluid. Rarely communicate with the tracheobronchial tree unless infected.
Presentation: Asymptomatic compression, recurrent infection (if communication established), dyspnoea from airway compression. Mediastinal cysts present with dysphagia, cough, or stridor depending on position.
Treatment: Complete surgical excision — prevents infection, haemorrhage, and rarely malignant transformation. VATS is preferred for accessible cysts. Incomplete excision risks recurrence.
Congenital cystic adenomatoid malformation (CCAM / CPAM)
Also known as CPAM (congenital pulmonary airway malformation). A hamartomatous lesion — normal airway epithelium without alveolar differentiation, with communication to the tracheobronchial tree (unlike sequestration). Affects a single lobe in 95% of cases.
| Type | Description | Cyst size | Features |
|---|---|---|---|
| 0 | Tracheal/bronchial origin | Tiny | Incompatible with life; acinar dysplasia |
| 1 (most common) | Bronchial/bronchiolar origin | Large (>2 cm) | Single or multiple large cysts; excellent prognosis |
| 2 | Bronchiolar origin | Medium (0.5–2 cm) | Multiple cysts; associated with sequestration and other anomalies |
| 3 | Bronchiolar/alveolar | Microscopic | Solid appearance; associated with hydrops |
| 4 | Distal acinar origin | Large | Risk of malignant transformation (pleuropulmonary blastoma) |
Treatment: Elective lobectomy is recommended for all diagnosed CCAM — even asymptomatic cases — due to risk of recurrent infection, pneumothorax, haemoptysis, and malignant transformation. VATS lobectomy is the preferred approach in experienced centres.
Congenital lobar emphysema (CLE)
Progressive hyperinflation of one or more lobes due to ball-valve bronchial obstruction. Affects the LUL most commonly (43%), followed by RML (32%) and RUL (20%). Bilateral or multilobe involvement is rare.
Presentation: Progressive respiratory distress in the neonatal period or early infancy — tachypnoea, wheeze, and mediastinal shift. On CXR: hyperinflated hyperlucent lobe with mediastinal shift and compression collapse of adjacent lobes.
Treatment: Emergency lobectomy in severe cases causing respiratory distress. Mild or asymptomatic CLE may be observed — some improve with resolution of the ball-valve obstruction. Lobectomy is curative.
Ex-utero intrapartum treatment (EXIT) is used for large foetal lung masses causing extrinsic tracheal compression and predicted airway compromise at delivery. The foetus is partially delivered while remaining on uteroplacental circulation, the airway is secured under direct vision, and the mass is either partially debulked or a tracheostomy placed — all before the umbilical cord is cut and the foetus fully delivered.
All clinical content should be verified against current guidelines before clinical application. This resource is intended for revision and educational purposes only.
Standard textbooks
- Shields TW, LoCicero J, Reed CE, Feins RH. General Thoracic Surgery. 7th ed. Lippincott Williams & Wilkins.
- Sellke FW, del Nido PJ, Swanson SJ. Sabiston & Spencer Surgery of the Chest. 9th ed. Elsevier.
- Pearson FG, et al. Thoracic Surgery. 3rd ed. Churchill Livingstone.