Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . There is a retrocardiac left lower lobe opacity which may represent pneumonia . There is blunting of the left costophrenic angle which may indicate a small left pleural effusion . The right lung is clear . No pneumothorax . Heart size is top normal . There is scoliosis and degenerative changes in the shoulders .
    OUTPUT:
    
Retrocardiac opacity in the left lower lobe may represent pneumonia . Likely small left pleural effusion .