The frontal chest x-ray shows a zone of opacification silhouetting the right heart border.

The lateral chest x-ray shows abnormal chest wall with severe pectus excavatum.

Silhouetting of the right heart border can be due to 3 causes.

• Right middle lobe consolidation.
• Right middle lobe collapse.
• Pectus excavatum due to displacement of the heart by the depressed sternum.

Bottom line is frontal chest x-ray in a patient with pectus excavatum can simulate right middle lobe disease.

With thanks to Dr. Faheem Afzal for the images.

Reference: Grainger & Allison’s Diagnostic Radiology, 6th Edition.