On HRCT chest, a patient with progressive dyspnoea shows bilateral subpleural reticulation, honeycombing in the basal posterior zones, and traction bronchiectasis without ground-glass opacity predominance. The UIP (usual interstitial pneumonia) pattern is confirmed. Which feature, if present, would favour a diagnosis of hypersensitivity pneumonitis rather than IPF?
- A Upper-lobe predominance with mosaic attenuation and centrilobular nodules ✓
- B Subpleural sparing of honeycombing
- C Peripheral traction bronchiectasis
- D Bibasal volume loss
Correct answer: A. Upper-lobe predominance with mosaic attenuation and centrilobular nodules
Explanation
Hypersensitivity pneumonitis (HP) classically shows upper and mid-lobe predominance, mosaic attenuation due to air-trapping (best seen on expiratory CT), and centrilobular micronodules — features that distinguish it from UIP/IPF which is basal and peripheral. Subpleural sparing and peripheral traction bronchiectasis are features seen in UIP. Bibasal volume loss is non-specific.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.