Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . Retrocardiac opacity on the frontal view corresponds with a left pleural effusion . There is also likely compressive left lower lobe atelectasis . The right lung is clear . No pneumothorax though skin folds project over the lung apices simulating pneumothorax . Cardiomediastinal silhouette appears stable . Bony structures are intact .
    OUTPUT:
    
Left pleural effusion likely with compressive lower lobe atelectasis . Followup to resolution advised .