This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory, Subject name: Medicine
What diagnosis is suggested by these spirography findings? 
Select and explain. 
A. Intrathoracic localized obstruction, B. Fixed inspiratory obstruction, C. Pneumothorax, D. Restrictive lung disease
A: Intrathoracic localized obstruction
Answer: A: Intrathoracic localized obstruction 
Explanation: Answer A. Intrathoracic localized obstructionAn intrathoracic localized obstruction is demonstrated on spirography. The patient underwent flexible fiberoptic bronchoscopy, which revealed nearly complete (greater than 90%) occlusion of the distal trachea by a vascular mass. The patient recovered after endoscopic laser ablation of the mass.