Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A retrocardiac opacity is present and of uncertain etiology . The lungs are otherwise clear . There is mild pulmonary edema . There is no pleural effusion or pneumothorax . The mediastinal contours are normal . The aorta is tortuous and calcified . The heart size is moderately enlarged . Calcified densities in the left apex are noted .
    OUTPUT:
    
1 . Retrocardiac opacity , likely hiatal hernia or tortuous aorta or aneurysm . Other etiologies could include atelectasis , though these are thought to be less likely . A lateral view of the chest is recommended when the patient is clinically stable . 2 . Mild pulmonary edema and moderate cardiomegaly .