A 45-year-old non-smoking woman presents with progressive dyspnea over 18 months. HRCT shows bilateral basal honeycombing with traction bronchiectasis and no ground-glass opacity predominance. BAL shows >80% lymphocytes. Which ILD pattern does the HRCT show and what does the BAL suggest?
- A UIP pattern on HRCT; BAL lymphocytosis suggests concurrent hypersensitivity pneumonitis, not IPF ✓
- B NSIP pattern on HRCT; BAL lymphocytosis suggests IPF
- C DIP pattern on HRCT; consistent with smoking-related ILD
- D COP pattern on HRCT; BAL confirms organizing pneumonia
Correct answer: A. UIP pattern on HRCT; BAL lymphocytosis suggests concurrent hypersensitivity pneumonitis, not IPF
Explanation
Bilateral basal honeycombing with traction bronchiectasis is the hallmark of a usual interstitial pneumonia (UIP) pattern on HRCT. However, BAL lymphocytosis >30–40% is atypical for IPF (which typically shows neutrophilic predominance) and raises the possibility of hypersensitivity pneumonitis or NSIP. In a non-smoker with BAL lymphocytosis, HP must be excluded before diagnosing IPF. BAL lymphocytosis in a UIP pattern should prompt detailed HP exposure history and further evaluation.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.