Usual interstitial pneumonia (UIP) is the histopathological pattern underlying idiopathic pulmonary fibrosis (IPF). Which combination of features on surgical lung biopsy is DIAGNOSTIC of UIP?
- A Uniform inflammatory infiltrate with diffuse alveolar damage and hyaline membranes
- B Spatial and temporal heterogeneity — areas of dense fibrosis with honeycombing adjacent to relatively normal lung with fibroblastic foci ✓
- C Non-necrotising granulomas in a peribronchial distribution with airspace consolidation
- D Organising pneumonia with Masson bodies (plugs of granulation tissue) in alveolar ducts
Correct answer: B. Spatial and temporal heterogeneity — areas of dense fibrosis with honeycombing adjacent to relatively normal lung with fibroblastic foci
Explanation
UIP (IPF) is characterised by spatial heterogeneity (patchy fibrosis with normal lung next to fibrotic areas) and temporal heterogeneity (mixture of established fibrosis/honeycombing and fresh fibroblastic foci), predominantly in the subpleural and basal regions. Fibroblastic foci represent the leading edge of active fibrogenesis. Diffuse alveolar damage characterises ARDS; organising pneumonia characterises COP/BOOP.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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