Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiograph demonstrates well expanded lungs . Posterior to the heart is a heterogeneous soft tissue lesion . The trachea is slightly deviated leftwards . No pleural effusion or pneumothorax . Heart size , mediastinal contour , and hila are unremarkable .
    OUTPUT:
    
1 . Heterogeneous retrocardiac soft tissue structure may be a hiatal hernia . Correlation with surgical history is recommended . 2 . Mild leftwards deviation of trachea . Additional surgical history is recommended to assess whether this is postsurgical .