Objective: Unilateral pulmonary artery agenesis (UPAA), a rare congenital anomaly that is frequently associated with other cardiovascular abnormalities, is usually diagnosed in childhood. Most patients who have no associated cardiac anomalies have only minor or absent symptoms and survive into adulthood. The conditions of such patients are frequently misdiagnosed in adulthood. In this report, we describe six patients with UPAA in whom the diagnosis was first established in adulthood. The varied clinical presentation of these patients is reviewed and the relative effectiveness of a variety of diagnostic tests is compared.
Subjects and methods: During the period January 1987 through December 1990, six male patients, aged 17 to 20 years, were found to have UPAA at the time of their medical screening for enrollment into the armed forces. The diagnosis was based on history, clinical and imaging examinations, including chest radiography, ventilation-perfusion lung scan, digital subtraction angiography (DSA), computed tomography (CT), and magnetic resonance imaging (MRI).
Results: In four of the patients, the UPAA was on the left side and in two it was on the right. A right aortic arch was present in three patients and other cardiovascular anomalies were found in three. Pulmonary function studies showed a mild restrictive pattern in four. In contrast to previous reports, the ventilation scan showed a diminished "wash in" and "equilibrium" phase without a delayed "wash out" phase on the affected side in all patients. Selective bronchography through the fiberoptic bronchoscope revealed ipsilateral mixed-type bronchiectasis in two of four patients studied, a finding of clinical significance that has not been described previously. In all cases, the diagnosis was made by DSA. CT of the thorax (n = 6) and MRI (n = 4) were diagnostic in all cases in which they were performed, but added no significant information.
Conclusion: UPAA is frequently misdiagnosed in adulthood and is often not considered in the differential diagnosis of the unilateral hyperlucent lung. Clinicians and radiologists should be aware of the possibility of undiagnosed cases in adults, with many atypical characteristics.