A 38-year-old non-smoker woman presents with progressive dyspnea over 2 years. HRCT shows bilateral ground-glass opacities with traction bronchiectasis and peripheral honeycombing. Bronchoalveolar lavage shows >20% lymphocytes. Lung biopsy shows temporal homogeneity, uniform fibrosis without honeycomb, and absence of fibroblastic foci. This pattern is consistent with:
- A Usual Interstitial Pneumonia (UIP)
- B Nonspecific Interstitial Pneumonia (NSIP) ✓
- C Desquamative Interstitial Pneumonia (DIP)
- D Cryptogenic Organizing Pneumonia (COP)
Explanation
NSIP (Nonspecific Interstitial Pneumonia) is characterized by temporally uniform fibrosis with/without ground-glass (the cellular subtype being more responsive to steroids), preserved alveolar architecture, absence of honeycombing on histology, and bilateral basal ground-glass on HRCT. BAL lymphocytosis >15% supports NSIP or HP over UIP. NSIP is commonly associated with connective tissue diseases (SSc, PM/DM, Sjögren's) and is more common in younger non-smoking women — this clinical profile fits. UIP shows temporal heterogeneity with honeycombing, fibroblastic foci, and subpleural accentuation. DIP shows diffuse macrophage accumulation. COP shows patchy consolidation with peribronchial distribution.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.