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Congenital lung malformations (CPAM, sequestration, congenital lobar emphysema)
Most congenital lung malformations are now found on fetal ultrasound; before birth management is decided by the risk of hydrops (the CVR index), and after birth by symptoms, recurrent infection and the concern of malignancy.
Why it matters in the exam
CPAM (congenital pulmonary airway malformation) is a lung mass with cysts or solid tissue that receives a pulmonary blood supply. A CVR (lesion volume divided by head circumference) above 1.6 predicts a high risk of hydrops, and in that case — and also with mediastinal shift or hydrops — delivery is planned in a tertiary centre. In a microcystic lesion at risk of hydrops the mother is given betamethasone, and for a dominant large cyst an in-utero shunt into the amniotic cavity is considered.
Pulmonary sequestration is lung tissue without a normal connection to the bronchial tree that receives a systemic arterial supply — usually a branch of the aorta — so identifying the artery before surgery is important. Intralobar sequestration lies within the lung's pleura, usually in the left lower lobe, drains into the pulmonary veins and presents with recurrent infection; extralobar sequestration has its own pleura, drains into systemic veins, is found in the newborn, sometimes below the diaphragm, and comes with other anomalies such as CDH. Congenital lobar emphysema usually affects the left upper lobe: the lobe is over-inflated and pushes the mediastinum; a chest drain must not be inserted by mistake as if it were a pneumothorax.
Developmentally the lung passes through an embryonic stage, a pseudoglandular stage (when dichotomous branching of the airways down to the terminal bronchioles takes place), a canalicular stage, a saccular stage and an alveolar stage — and the alveolar stage continues for years after birth. A symptomatic lesion is resected at any age (usually lobectomy, now also thoracoscopic). For an asymptomatic lesion many resect at a few months of age because of the risk of infection and of pleuropulmonary blastoma (PPB), which looks like a cystic CPAM on imaging and is linked with DICER1 changes; others prefer observation.
Key points
- CVR above 1.6 — hydrops risk.
- Microcystic lesion at risk — betamethasone for the mother.
- Sequestration — systemic arterial supply.
- Congenital lobar emphysema — left upper lobe, no drain.
- Concern about PPB supports elective resection.
Summary table
| Lesion | Blood supply | Feature | Treatment |
|---|---|---|---|
| CPAM | Pulmonary | Cysts or solid tissue; CVR above 1.6 — hydrops risk | Prenatal: steroids or shunt; postnatal: resection for symptoms or elective |
| Intralobar sequestration | Systemic (aorta) | Left lower lobe, recurrent infection | Resection; identify the systemic artery |
| Extralobar sequestration | Systemic | Own pleura, associated anomalies, sometimes below the diaphragm | Resection or observation by symptoms |
| Congenital lobar emphysema | Pulmonary | Over-inflated left upper lobe, mediastinal shift | Lobectomy if symptomatic; no chest drain |
| Bronchogenic cyst | — | Mediastinal cyst, often below the carina | Excision |
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Sources
- Holcomb and Ashcraft's Pediatric Surgery, 7th edition (2019) — Congenital Bronchopulmonary Malformations
- APSA Fetal Diagnosis and Therapy: Prenatal management of congenital lung malformations (systematic review), 2020 — CVR, steroids and delivery planning
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.