This chest x-ray shows tracheal deviation to the right. There is no pleural effusion on the left, and there is overall volume loss of the right hemithorax, compared with the left. The mediastinum is therefore PULLED to the right.
Bronchoscopy showed a cancer occluding the right lower lobe bronchus. The x-ray shows right lower lobe collapse (ringed). Although the mass itself is not seen clearly, collapse of a lung lobe in an adult should raise the suspicion of a malignant process.