Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear except for a very small 2 mm nodule that is dense in the left upper lobe : it could be a calcified granuloma versus a small bone island of the posterior portion of fourth rib . The right superior paramediastinal region is lightly widened ; it could only be tortuous vessels or mediastinal lipomatosis but an underlying mass can not be excluded . The cardiac contour is normal . There is no pleural effusion and no pneumothorax . The patient has a left humeral prosthesis and extensive dorsal spine surgery with two fusion rods . The patient is known for ankylosing spondylitis .
    OUTPUT:
    
The right superior paramediastinal region is slightly widened : it could only be secondary to tortuous vessels or lipomatosis . If the patient has other previous exam , it will allow us to see if it is stable . If this is impossible , a CT scan is suggested .