FINDINGS:
There is a retrocardiac opacity concerning for pneumonia.  The right lung is
 clear.  The cardiomediastinal silhouette and hilar contours are within normal
 limits.  There is no pleural effusion or pneumothorax.

IMPRESSION:
Retrocardiac opacity compatible with pneumonia.
 
 RECOMMENDATION(S):  Repeat chest x-ray following treatment is recommended.