Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Dense consolidation in the retrocardiac left lung base , is concerning for an acute infectious process . There is a small left pleural effusion . The cardiomediastinal and hilar contours are stable , with heart in the upper limits of normal . There is no intra-abdominal free air .
    OUTPUT:
    
Left lower lobe pneumonia . Recommended follow - up chest radiographs in ___ weeks to document resolution .