Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours are unchanged the heart size within normal limits . Asymmetric 10 mm focal opacity projecting over the left first costochondral junction on the prior examination now appears to persist , projecting over the medial left upper lobe . Remainder of the lungs are clear . There are no pleural effusions or pneumothoraces .
    OUTPUT:
    
Persistent 10 mm focal opacity projecting over the medial aspect of the left upper lobe . Nonemergent chest CT is recommended for further assessment .