A 65-year-old non-smoker woman presents with progressive dyspnea. HRCT shows bilateral basilar honeycombing with traction bronchiectasis. Biopsy shows temporal heterogeneity — areas of fibrosis and honeycombing adjacent to relatively normal parenchyma — with fibroblastic foci at the leading edge. This pattern is:

• A Nonspecific interstitial pneumonia (NSIP)
• B Desquamative interstitial pneumonia (DIP)
• C Usual interstitial pneumonia (UIP) — pattern of idiopathic pulmonary fibrosis ✓
• D Cryptogenic organizing pneumonia (COP)

Explanation

Usual interstitial pneumonia (UIP) is the histological pattern diagnostic of idiopathic pulmonary fibrosis (IPF), characterized by spatial and temporal heterogeneity — patchy fibrosis and honeycombing coexisting with normal lung — with fibroblastic foci at the advancing edge of fibrosis. NSIP shows temporally uniform fibrosis without fibroblastic foci and has a better prognosis. DIP shows macrophage accumulation in air spaces (related to smoking). COP (previously BOOP) shows intraluminal fibroblastic plugs in bronchioles and alveoli.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.