Hyperlucent Lung Syndrome Associated with Persistent Foramen Ovale and Bilateral Bullous Emphysema

A 61-year-old white male presented to the hospital with progressively worsening shortness of breath. He had chronic respiratory insufficiency from emphysema and had a tracheostomy tube connected to oxygen via collar. Because of the exacerbation of chronic obstructive pulmonary disease and respiratory distress, the tracheostomy tube was attached to mechanical ventilation. The chest x-ray was remarkable for considerable hyperlucency over the right hemithorax as compared with the left. There were no abnormal acute lung infiltrates. The patient was diagnosed with unilateral hyperlucent lung syndrome.

Figure 1. Chest x-ray shows that the right hemithorax is hyperlucent compared to the left.

Differential diagnosis. The differential diagnosis of unilateral hyperlucent lung syndrome includes the possibility of pathology either on the hyperlucent side or on the contralateral side. 

Pathology on the hyperlucent side would include a unilateral loss of chest wall mass on the affected side, unilateral emphysema (eg, Swyer-James syndrome), large bullae on the affected side, attenuation of the vascular markings on the affected side, such as would occur with large unilateral pulmonary emboli (Westermark sign), and air trapping with “check valve” mechanism from an endobronchial tumor or foreign body in 1 of the central airways of the affected side.

Pathology on the nonhyperlucent side would include a layered out pleural effusion or pleural thickening, unilateral lung infiltrate (acute or chronic) such as an infiltrative pneumonic process, an infiltrative neoplasm, and radiation pneumonitis. 

Laboratory tests. In view of his respiratory distress and the unilateral hyperlucent lung, a CT of the chest was ordered to rule out pulmonary embolism. The scan showed no pulmonary emboli. There was upper lobe emphysema, which was present symmetrically on both sides and therefore could not be responsible for the unilateral hyperlucency. The CT scan showed significantly less chest wall muscle mass on the right (hyperlucent) side as compared with the left. 

On inspection of the chest wall, we found a marked reduction of pectoral muscle mass on the right (hyperlucent) side. There were no surgical scars. The patient claimed that this asymmetry of his chest wall was present from birth. Echocardiogram showed the presence of a patent foramen ovale (PFO) or a small atrial septal defect (ASD). Based on the history of a unilateral absence of pectoralis major muscle since childhood, as well as the presence of a PFO/ASD, a diagnosis of Poland syndrome was made.

Figure 2.The right chest wall shows absence of the pectoralis major muscle.

Discussion. The diagnosis of Poland syndrome is a clinical one. The syndrome is characterized most commonly by absence or diminished mass of the pectoralis major muscle on one side of the chest. The right side is more frequently affected and the syndrome is more common in males. The sternal origin of the pectoralis muscle is most commonly involved. Other presentations, which may or may not be present, include dextrocardia, syndactyly, brachydactyly (short fingers and toes), and hypoplasia of ribs. A PFO or ASD is occasionally seen in Poland syndrome and may be associated with pulmonary stenosis. Our patient had the PFO defect but pulmonary stenosis was not documented. 

Poland syndrome is a rare congenital disease with an incidence of 1 in 30,000 live births. Although the etiology is unknown, it is currently believed that disruption of the embryonic subclavian artery during the 6th week of gestation causes the abnormalities observed in the syndrome. 

Figure 3. A chest CT scan shows absence of the right pectoralis major muscle.

Figure 4. The Doppler echocardiogram shows that there is a patent foramen ovale/atrial septal defect.

Treatment. There is no specific treatment for Poland syndrome. Complications have to be managed as and when they occur. The chest wall defects may require reconstructive surgery.

Outcome of the case. Our patient was a case of emphysema with bilateral bullae and a smoking history. We speculate that our patient with a smoking history was more predisposed to develop bullous emphysema because of Poland syndrome.  

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