Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is likely within normal limits . The mediastinal and hilar contours are unremarkable , and no pulmonary edema is present . A large left pleural effusion is present along with compressive atelectasis of the left lung base . The right lung is clear . No pneumothorax is identified . There are mild degenerative changes seen in the thoracic spine .
    OUTPUT:
    
Large left pleural effusion with compressive left basilar atelectasis .