A full-term asymptomatic female neonate with a systolic murmur was referred to our department for a cardiology review.

The echocardiogram failed to show the left pulmonary artery branch. The remaining examination was normal. For clarification, a computed tomography angiogram was performed. It showed the left pulmonary artery branch arising from the anterior aspect of the proximal descending thoracic aorta (Figures 1 and 2), 13mm below the area from which the left subclavian artery arises. A diagnosis of anomalous origin of the left pulmonary artery was made.

Figure 1.

Axial view computed tomography angiography showing the left pulmonary artery branch arising from the descending aorta.

Ao: aorta; LPA: left pulmonary artery; MPA: main pulmonary artery; RPA: right pulmonary artery.

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Figure 2.

Posterolateral view of three-dimensional computed tomography angiography reconstruction showing the left pulmonary artery branch arising from the anterior aspect of the proximal descending thoracic aorta.

AAo: ascending aorta; LPA: left pulmonary artery; DAo: descending aorta.

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To quantify pulmonary pressure, the patient underwent cardiac catheterization (Figures 3 and 4) at one year of age, which excluded pulmonary arterial hypertension.

Figure 3.

Pulmonary angiography showing the absence of the left pulmonary artery branch.

RPA: right pulmonary artery; MPA: main pulmonary artery.

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Figure 4.

Aortic angiography demonstrating anomalous origin of the left pulmonary artery from the descending thoracic aorta.

LPA: left pulmonary artery; DAo: descending Aorta.

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To the best of our knowledge, only two other cases with the same anatomical features have been reported in the literature. In the majority of cases, the right pulmonary artery branch is involved and usually arises from the posterolateral aspect of the ascending aorta.

The authors have no conflicts of interest to declare.