Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded . There is well - defined consolidative opacity at the left lung base with obscuration of the left diaphragm . The right lung is otherwise clear . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is unremarkable .
    OUTPUT:
    
Well - defined consolidative left basilar opacity which has an unusual appearance for pneumonia and underlying mass may be present . Further assessment with chest CT is recommended .