Asymmetrical Hilar Enlargement in an Asymptomatic Patient

Figure 1: Pulmonary Stenosis Asymmetric unilateral enlargement of the left pulmonary artery is highly suggestive of pulmonary stenosis, especially in the appropriate clinical context i.e findings of a heart murmur on cardiac assessment. This appearance is attributed to the stenotic jet stream, which is preferentially directed towards the left pulmonary artery and which results in focal post-stenotic dilatation where the jet impacts the left pulmonary arterial wall. In some cases, enlargement of the main pulmonary artery can also be appreciated, as well as right ventricular enlargement in severe cases. Asymmetric enlargement of the left compared with the normal right pulmonary artery is the “auntminnie” characteristic of this condition.