Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . No effusion or pneumothorax is present . A 1 - cm density adjacent to the right anterior first rib is most likely costochondral calcification but the presence of a pulmonary nodule in this region can not be excluded . Heart and mediastinal contours are normal .
    OUTPUT:
    
Equivocal right upper lung nodule most likely represents costochondral calcification . A repeat radiograph in lordotic positioning may be helpful to better characterize .