Autopsy of a 35-year-old woman who died of severe headache and renal failure shows blood pressure of 230/140 mmHg antemortem. Histology of small arteries reveals smudgy, eosinophilic, amorphous pink material replacing the vessel wall with luminal narrowing. This pattern of necrosis is characteristic of:

• A Caseous necrosis due to mycobacterial infection
• B Fat necrosis secondary to lipase release
• C Fibrinoid necrosis due to immune-mediated vascular injury ✓
• D Gangrenous necrosis of the arterial wall

Explanation

Fibrinoid necrosis features deposition of plasma proteins, especially fibrin, along with immunoglobulins in damaged vessel walls, giving a bright eosinophilic homogenous appearance. It occurs in malignant hypertension, polyarteritis nodosa, and immune complex vasculitis such as Aschoff bodies and lupus vasculitis. Caseous necrosis is granulomatous and cheese-like, fat necrosis involves adipose tissue, and gangrene requires grossly evident ischemic tissue death, none of which fits this vascular lesion.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.