by Dr Noreen Norfaraheen Lee Abdullah MD (UKM), MMed Radiology (UKM), AM(Mal)

Answer to Case Of the Month 
Congenital Lobar Emphysema

Discussion of Findings
Chest Radiograph
The right hemithorax was more lucent when compared to the left. Herniation of the hyperlucent right lung into the left hemithorax was seen. There was mediastinal shift to the left. The right mid and lower zone demonstrated hyperinflation with flattening of the right hemidiaphragm. The vessels in the right upper lobe were crowded. This was consistent with compressed right upper lobe by the hyperinflated segments of the right lung. The contralateral lung was compressed by the shifted mediastinal structures.

CT Thorax
Two large cystic lesions were seen in the right middle lobe. They appeared thin walled, septated, air filled and within, it lacked vascular markings. They caused compression to the right upper and lower lobes resulting in vessel crowding. There was mediastinal shift to the left and compression of the left lung field. Air space opacities were seen in the apical segment of lower lobe and lingular segment of the left lung. The features were consistent with Congenital Lobar Emphysema.
Differential diagnosis of Congenital Cystic Adenomatoid Malformation Type I is also possible. In addition, there was left lung focal pneumonia.

Congenital lobar emphysema (CLE) is a relatively common problem in infancy. The presentation is varied; some are asymptomatic while others present with severe neonatal respiratory distress. Occasionally this condition is suspected in utero during sonography if an overexpanded lobe filled with fluid is identified. Progressive respiratory distress from birth reflects the degree of emphysema; symptoms are at their worst in the first month. Sometimes, the presentation is in later childhood or adulthood.

CLE causes overexpansion of a pulmonary lobe with resultant compression of the remaining ipsilateral lung. Mediastinal shift can compress the contralateral lung. The abnormality is congenital in origin. It results from collapse of the bronchus secondary to segmental bronchial cartilage underdevelopment. This causes loss of normal rigidity of the bronchus and leads to redundancy and mucosa crinkling. Together with bronchial wall collapse it leads to a focal ball valve obstruction. Air trapping in the involved lobe then occurs.

The mentioned pathology manifests as overdistension of a lobe with associated air trapping in the involved lobe and compressive changes in the remainder of the lung. Mediastinal shift away from the increased volume results in compression of the contralateral lung. CLE almost always involves one lobe, with rates of occurrence as follows:

  Left upper lobe - 41%

  Right middle lobe - 34%

  Right upper lobe - 21%

CLE has two forms:

  Hypoalveolar (fewer than expected number of alveoli)

  Polyalveolar (greater than expected number of alveoli)

Approximately 10% of patients have associated anomalies; congenital heart disease in particular. A screening echocardiogram examination will be appropriate.

Differential diagnosis that may be considered:

Congenital cystic adenomatoid malformation
Congenital lung cyst

Pneumothorax

Bronchial mucous plug

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Last Updated:
Tuesday, 04 January 2005