Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: An endotracheal tube terminates in the proximal left mainstem bronchus , and recommend pullback of the tube . A nasogastric tube terminates subdiaphragmatic and beyond the view of this radiograph . There is a left basilar opacity likely reflecting pleural effusion and underlying left lower lobe collapse and / or consolidation . A left upper mediastinal opacity is new from ___ and raises concern for a mass or aortic aneurysm . There is mild vascular plethora , a without overt CHF . In the right lung , no focal consolidation or gross effusion . The cardiac silhouette is obscured on the left side , limiting assessment of cardiac size .
    OUTPUT:
    
1 . Left basilar pulmonary opacity likely represents a moderate pleural effusion with associated compressive atelectasis , and superimposed infection can not be excluded . 2 . Left upper mediastinal opacity may represent a mass , given the reported history of lung cancer ( source uncertain ) . The differential diagnosis could include an aortic aneurysm . Recommend further evaluation with CT . 3 . Endotracheal tube terminates in the proximal left mainstem bronchus . Recommend pullback of tube approximately 2 cm .