2 radiographs of the same patient but with different exposures.
This 46 year old smoker presented with fever and cough. A CXR was done.
It showed a triangular opacity at the right lower zone obliterating the right heart border. This is consistent with right middle lobe collapse consolidation. The patient was referred to a respiratory physician for bronchoscopy to assess the cause of bronchial obstruction. What is the most likely cause of obstruction?