A 25-year-old female presents with progressive dyspnea for one year. CXR shows interstitial opacities and spirometry shows an obstructive pattern. What is the diagnosis?: (A) Non-specific interstitial pneumonitis, (B) Pulmonary Lymphangioleiomyomatosis, (C) Idiopathic pulmonary fibrosis, (D) Pulmonary Alveolar Proteinosis
Answer is B. Interstitial lung disease leads to the restrictive pattern on spirometry. However tuberous sclerosis and Lymphangioleiomyomatosis are exceptions and lead to an obstructive pattern. Pulmonary LAM presents in young females with emphysema, recurrent pneumothorax and chylous pleural effusion.