Usual interstitial pneumonia (UIP) pattern on lung biopsy is characterized by which combination of histological features?

• A Temporal and spatial heterogeneity with fibroblastic foci and honeycombing ✓
• B Uniform temporal appearance with diffuse alveolar damage and hyaline membranes
• C Organizing pneumonia with fibroblastic plugs filling alveolar spaces
• D Eosinophilic infiltrate with plasma cells and germinal center formation

Explanation

UIP (the histological pattern underlying IPF) shows temporal and spatial heterogeneity: areas of dense fibrosis with honeycombing adjacent to normal lung and active fibroblastic foci. This patchwork appearance — old fibrosis, new fibroblastic foci, and normal lung in the same biopsy — is the hallmark. It differs from NSIP (uniform/temporal homogeneity) and COP (organizing pneumonia pattern).

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.