CASE PRESENTATION: A 25-years-old male with past medical history of recurrent pericardial effusion, limited joint mobility, cognitive deficiency and recurrent airway infections originally evaluated for progressive dyspnea. He underwent bronchoscopy and was diagnosed with multi-level airway stenosis compromising the right nasal, subglottic region, trachea and left main bronchus. The patient was treated with repeated balloon dilations and intra-lesional steroid injections every 2 months. One year later presenting to the emergency department with progressive dypsnea. The physical examination was remarkable for right nasal stenosis, cervical stridor and desaturation requiring non-invasive ventilation. The CT scan showed complete collapse of the left lung and stenosis of the left main bronchus(100%), trachea(75%), and bronchus intermedius(35%). After admission he developed respiratory arrest requiring intubation (ETT #6) under bronchoscopic guidance with a 4mm pediatric scope after several failed attempts at direct laryngoscopy. Then, the patient was admitted to ICU requiring tracheostomy, antibiotics and pulses of steroids. The airway tissue biopsy revealed patchy chronic inflammation, mucosal fibrosis with granulation tissue, hemosiderin deposition and scattered eosinophils. Twenty days later the patients was discharged on oral steroids. A genetic consultation showed mutation in the SMAD4 gene suggesting MS. Losartan and Etanercept were added to the treatment with successful tapering of prednisone. Since then the patient has undergone stent placement, balloon dilation and intraluminal steroids. No further episodes of acute respiratory failure have occurred.