Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable frontal supine image of the chest . There is a dense left lung opacity ocuppying a significant portion of the left hemithorax . Some aerated lung seen at the apex A nodular opacity seen overlying the right lower lung may represent a nipple shadow . The right lung is well expanded and clear . There is no pneumothorax . The cardiomediastinal silhouette is partially obscured by the left lung base opacity , but appears similar to prior exam noting probable mild shift to the right .
    OUTPUT:
    
1 . Dense left lung base opacity , suspicious for a pleural effusion with likely associated atelectasis and possible parenchymal disease . Mild shift of the mediastinum to the right . PA and lateral chest radiographs or chest CT could be pursued for further evaluation . 2 . Nodular opacity overlying the right lower lobe may represent a nipple shadow , and should be followed on subsequent studies .