A 45-year-old woman presents with progressive dyspnea and a non-productive cough. HRCT chest shows diffuse, bilateral, ground-glass opacities with a 'crazy-paving' pattern. Bronchoalveolar lavage returns milky fluid that is periodic acid-Schiff (PAS) positive. Which of the following is the most likely diagnosis?
- A Pulmonary alveolar proteinosis ✓
- B Pulmonary edema
- C Lipoid pneumonia
- D Bronchioloalveolar carcinoma
Correct answer: A. Pulmonary alveolar proteinosis
Explanation
Pulmonary alveolar proteinosis (PAP) classically presents with crazy-paving pattern on HRCT and milky bronchoalveolar lavage fluid that is PAS-positive due to accumulation of surfactant-like lipoproteinaceous material. Pulmonary edema can show crazy-paving but BAL is not milky or PAS-positive. Lipoid pneumonia shows fat attenuation. Bronchioloalveolar carcinoma (lepidic-predominant adenocarcinoma) may show ground-glass but not PAS-positive BAL.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.