Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were reviewed . Left upper lobe collapse is due to a large lobulated left hilar mass obstructing the upper lobe bronchus . Thickening of the right paratracheal stripe is a strong indication of contralateral mediastinal adenopathy , also involving the left lower paratracheal station and aortopulmonic window . Elevation of the left hemidiaphragm is due in part to atelectasis but is severe enough to suggest phrenic nerve impingement by central tumor . Apparent thickening of the left lung apical pleural margin is actually due to upper lobe atelectasis above the elevated major fissure . Pleural surfaces are normal . Heart size is not enlarged . Right lung is clear .
    OUTPUT:
    
Bronchial obstruction by large , presumably malignant , left hilar mass responsible for left upper lobe collapse , possible left phrenic nerve palsy , extending to ipsilateral and contralateral medistinal lymph nodes .