A 42-year-old woman presents with progressive dyspnea over 8 months. HRCT shows diffuse thin-walled cystic lesions uniformly distributed throughout both lung fields with no zonal predominance. Pulmonary function tests show obstructive pattern. What is the most likely diagnosis?
- A Centriacinar emphysema
- B Pulmonary Langerhans cell histiocytosis
- C Lymphangioleiomyomatosis (LAM) ✓
- D Usual interstitial pneumonia (UIP)
Correct answer: C. Lymphangioleiomyomatosis (LAM)
Explanation
Lymphangioleiomyomatosis (LAM) is a rare disease of women characterized by diffuse thin-walled cysts uniformly distributed throughout the lungs (no zonal predominance), causing an obstructive pattern on PFT. Centriacinar emphysema shows upper lobe predominance. PLCH shows upper lobe predominance with bizarre-shaped cysts and nodules. UIP shows basal subpleural honeycombing with restrictive pattern.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.