Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: On the lateral view , there is a 2 .8 cm rounded opacity of unclear etiology , projecting over the posterior aspect of the cardiac silhouette . Otherwise , no definite focal consolidation is seen . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
2 .8 cm rounded opacity seen on the lateral view projecting over the posterior aspect of the cardiac silhouette , of unclear etiology . Suggest nonurgent chest CT for further evaluation .