Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP , semi upright portable chest radiograph was provided . Patient is slightly rotated which limits evaluation . The relative opacity at the left lung base could represent an early pneumonia otherwise lungs are clear . No effusion or pneumothorax . The heart size appears normal .
    OUTPUT:
    
Vague opacity at the left lung base could represent pneumonia though patient rotation limits evaluation .