Congenital lobar emphysema (CLE) is a congenital anomaly characterized by hyperinflation of a lung lobe. Most commonly affects the left upper lobe (42%) and right middle lobe (35%). Pathophysiology involves bronchial cartilage deficiency or dysplasia creating a check-valve (one-way valve) mechanism — air enters during inspiration but cannot exit during expiration, causing progressive hyperinflation. On CXR and CT, the affected lobe appears markedly hyperinflated — hyperlucent, compressing ipsilateral normal lobes and causing mediastinal shift. May present with respiratory distress at birth or be recognized with recurrent respiratory symptoms in infancy. Differential diagnosis from CPAM and CDH is needed. Lobectomy is curative in symptomatic cases. Conservative observation may be preferred in asymptomatic cases.
Age Range
0-0.5
Peak Age
0.05
Gender
Male predominant
Prevalence
Rare
The fundamental mechanism in CLE pathophysiology is bronchial cartilage deficiency or dysplasia (50% of cases). Normal bronchial cartilage provides structural support keeping the bronchial lumen open during expiration. With cartilage insufficiency, the bronchial wall collapses during expiration — creating a check-valve mechanism: during inspiration, negative intrapleural pressure opens the bronchus allowing air entry; during expiration, positive pressure compresses the bronchus preventing air exit. This vicious cycle leads to progressive hyperinflation. Other causes: mucosal folds, mucous plugging, external compression (aberrant vessel, lymphadenopathy), bronchial stenosis. The hyperinflation on CXR directly results from excessive air trapping — normal alveolar structures are preserved but overinflated (the term emphysema is somewhat misleading as there is no true alveolar destruction — the correct term is 'congenital lobar overinflation'). The hyperinflated lobe compresses surrounding structures. Reduced vascular markings on CT reflect stretching and compression of pulmonary arterial branches due to alveolar overdistension.
The signature finding of CLE is uniform (homogeneous) hyperinflation of a single lung lobe — affected lobe is hyperlucent, expanded, with decreased vascular markings and does NOT CONTAIN cystic structures. This last feature (absence of cysts) is the critical difference separating CLE from CPAM.
The most characteristic CXR finding of CLE is marked hyperinflation of a single lung lobe. The affected lobe occupies most of the ipsilateral hemithorax, appears hyperlucent (more black/radiolucent than normal) with decreased or absent vascular markings. Ipsilateral normal lobes are compressed and atelectatic. Mediastinal structures are displaced contralaterally. On immediate postnatal CXR, hyperinflation may not yet be apparent — as fetal lung fluid clears, hyperinflation becomes prominent over hours-days (during this period the lobe may appear fluid-filled and opaque — confused with CDH or CPAM).
Report Sentence
On CXR, the left upper lobe/right middle lobe shows marked hyperinflation with hyperlucent appearance and decreased vascular markings; mediastinal structures are displaced contralaterally; findings are consistent with congenital lobar emphysema.
CT confirms CLE diagnosis and provides surgical planning. The hyperinflated lobe shows very low density (near air density, -900 to -950 HU) with markedly attenuated/sparse vasculature. Adjacent ipsilateral lobes appear compressed and consolidated (atelectasis). Lobe boundaries are preserved — hyperinflated lobe pushes adjacent lobes but may herniate along fissures. CT excludes important differentials: discrete cystic structures of CPAM are absent (CLE shows uniform hyperinflation), no diaphragmatic defect or abdominal organs in thorax as in CDH, no parietal-visceral pleural separation as in pneumothorax.
Report Sentence
On CT, the left upper lobe/right middle lobe shows uniform hyperinflation with lobe density of ___ HU; vascular structures are markedly attenuated; no cystic structures are seen; adjacent lobes are compressed and atelectatic.
Mass effect of the hyperinflated lobe compresses ipsilateral adjacent lobes causing atelectasis. On CT, compressed lobes show high density (consolidation) — atelectatic lung tissue appears as dense tissue with decreased aeration. This compression may be both ipsilateral and contralateral. Fissure herniation — hyperinflated lobe herniating along fissure into adjacent lobe — is a finding quite specific to CLE.
Report Sentence
Adjacent ipsilateral lobes appear compressed and atelectatic due to mass effect of the hyperinflated lobe.
On prenatal US, CLE may appear as increased echogenicity and expansion of the affected lobe. Since fetal lungs are fluid-filled, the affected lobe appears more echogenic and larger than other lobes. Mediastinal shift may be seen. Prenatal diagnosis is difficult — similar appearance to microcystic CPAM. Some CLEs may spontaneously decrease in size prenatally.
Report Sentence
On prenatal US, an echogenic enlarged lobe is seen in the ___ hemithorax with mediastinal shift; CLE or CPAM should be considered.
The most important difference between CLE and CPAM is the absence of cystic structures. On CT, CLE shows uniform hyperinflation — the affected lobe is homogeneously aerated with preserved but expanded alveolar architecture. In CPAM, discrete cystic structures (large in type 1, small in type 2) are seen. This distinction also affects treatment planning — conservative observation is possible in asymptomatic CLE, while CPAM requires resection due to malignancy risk.
Report Sentence
No discrete cystic structures are seen in the hyperinflated lobe; the uniform hyperinflation pattern supports CLE diagnosis rather than CPAM.
Criteria
Bronchial cartilage absent or dysplastic. 50% of cases. Most common type.
Distinct Features
Progressive hyperinflation. Lobectomy needed in symptomatic cases. Conservative follow-up in asymptomatic.
Criteria
Obstruction due to mucosal folds, mucous plugging, or external compression (aberrant vessel). 25% of cases.
Distinct Features
In some cases, resolution possible with removal of obstruction.
Criteria
No identifiable etiology. 25% of cases.
Distinct Features
Pathological examination shows normal cartilage and mucosa. Neuromuscular dysfunction is considered.
Distinguishing Feature
CPAM has discrete cystic structures, CLE does not. CPAM shows cystic or mixed mass, CLE shows uniform hyperinflation. CT definitively shows this distinction.
Distinguishing Feature
In pneumothorax, visceral pleural line is seen and air collects outside parietal pleura — vascular markings completely absent. In CLE, no visceral pleural line, vascular markings reduced but present.
Distinguishing Feature
CDH has bowel loops in thorax and diaphragmatic defect. CLE shows hyperinflated lung lobe, intact diaphragm, no abdominal organs.
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
specialist-referralCLE management depends on symptom severity. Neonates with severe respiratory distress require emergency lobectomy — removal of hyperinflated lobe allows ipsilateral and contralateral lobes to re-expand. Moderately symptomatic cases undergo elective lobectomy after stabilization. Conservative observation may be preferred in asymptomatic cases. Lobectomy has >95% success rate with compensatory growth of remaining lobes. VATS is the minimally invasive approach. Prognosis is excellent. Associated cardiac anomalies (14%) should be investigated.
A congenital anomaly causing progressive respiratory distress in neonates. May be confused with tension pneumothorax — visibility of vascular structures within the lobe is critical in differential diagnosis (no vessels in pneumothorax). Emergent lobectomy is life-saving in severe cases. Conservative management is possible in mild cases as spontaneous improvement has been reported. Associated with congenital heart disease in 10-14% of cases. CT is the gold standard for diagnosis.