The chest x-ray shows

The PA chest x-ray shows obscuration of the right heart border by a density. The lateral chest x-ray shows severe form of pectus excavatum. There is no air space opacity or collapsed lung segment overlapping the hear in the lateral view.

3 causes of right heart border silhouetting are:

• Right middle lobe pneumonia involving the medial segment.
• Right middle lobe collapse involving the medial segment.
• Pectus excavatum.