Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a retrocardiac opacity in the left lower lobe concerning for pneumonia . Otherwise lungs are clear . There is no pleural effusion . Cardiomediastinal silhouette is unremarkable . Hilar and mediastinal contours are unremarkable . No pneumothoraces . Bones are intact .
    OUTPUT:
    
Left lower lobe pneumonia .