A 55-year-old non-smoker woman develops progressive exertional dyspnea and bibasal fine inspiratory crackles. CT shows bilateral ground-glass opacities with honeycombing predominantly in the subpleural regions. The surgical lung biopsy shows temporally and spatially heterogeneous fibrosis with fibroblastic foci. This pattern is called:
- A Non-specific interstitial pneumonia (NSIP)
- B Desquamative interstitial pneumonia (DIP)
- C Usual interstitial pneumonia (UIP) ✓
- D Organizing pneumonia (OP)
Explanation
The histological pattern of UIP — the substrate of idiopathic pulmonary fibrosis — is defined by temporal and geographic heterogeneity of fibrosis (areas of dense fibrosis adjacent to normal lung), subpleural/paraseptal distribution, honeycombing with cystic spaces lined by bronchiolar epithelium, and fibroblastic foci (the active leading edge of fibrosis). NSIP shows temporally uniform fibrosis without honeycombing, better prognosis, and is associated with CTD. DIP shows diffuse macrophage accumulation in alveoli in smokers. OP shows plugs of organizing fibrous tissue in alveolar ducts (Masson bodies).
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.