A 60-year-old man with long-standing diabetes develops an area of dry gangrene in the foot. Histological sections of the ischemic tissue show preservation of cell outlines, nuclear pyknosis, and loss of cytoplasmic basophilia, without neutrophilic infiltration. Which statement correctly explains why coagulative necrosis (compared to liquefactive necrosis) lacks early neutrophilic infiltration in ischemic tissue?

• A In coagulative necrosis, the denatured cytoplasmic proteins inhibit the complement pathways, preventing generation of C5a chemoattractant for neutrophils
• B Coagulative necrosis preserves the structural scaffold of denatured proteins, which physically blocks neutrophil diapedesis through the necrotic zone; liquefactive necrosis results from enzymatic dissolution which creates a liquid medium permitting neutrophil transit
• C The low pH of coagulative necrotic tissue acidifies the local environment, inhibiting neutrophil oxidative burst and preventing their survival in the ischemic zone
• D In ischemic coagulative necrosis, vascular supply is obliterated, preventing delivery of circulating neutrophils to the zone; peripheral inflammatory changes at the viable-necrotic junction occur once collateral vessels bring neutrophils to the edge of the infarct ✓

Explanation

Coagulative necrosis, characteristic of ischemic infarcts in most organs (except brain), shows preserved tissue architecture with protein denaturation but structural scaffold maintenance. The critical reason neutrophilic infiltration is delayed or absent centrally is the obliteration of blood supply in the infarcted zone — neutrophils simply cannot be delivered to the necrotic center. Neutrophils and macrophages accumulate at the viable-necrotic interface (the inflammatory 'zone of reaction') where patent vessels exist. Over days, macrophages enter and phagocytose debris via collateral circulation at the margins. In contrast, liquefactive necrosis (e.g., cerebral infarcts, abscess) involves enzymatic digestion by neutrophil-derived enzymes (cathepsins, elastase, MPO) that liquefy the tissue.

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

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Written and medically reviewed by the StethoPrep medical team.