A 55-year-old non-smoker woman with progressive dyspnea has a CT showing bilateral basal predominant honeycombing and traction bronchiectasis. Lung biopsy shows temporal heterogeneity with fibroblastic foci adjacent to dense collagen fibrosis and relatively normal lung. The pattern is:

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

Explanation

The histological pattern of temporal and spatial heterogeneity—fibroblastic foci (active fibrosis) alongside dense collagen scar and relatively preserved areas—is the hallmark of usual interstitial pneumonia (UIP), the pattern underlying idiopathic pulmonary fibrosis (IPF). NSIP shows uniform temporal appearance (all lesions at the same stage); COP shows polypoid plugs of granulation tissue in alveolar spaces; DIP shows diffuse macrophage filling of alveoli, typically in smokers.

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

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Written and medically reviewed by the StethoPrep medical team.