Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest radiographs were obtained . There is volume loss at the left lung base with area of focal opacity , likely due to atelectasis . The cardiac silhouette is moderately enlarged . Hilar and mediastinal contours are stable . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Left lung base atelectasis , pneumonia can not be excluded in the appropriate clinical setting .