A 60-year-old man with longstanding hypertension develops a pulsatile abdominal mass. Imaging reveals a 6 cm fusiform abdominal aortic aneurysm below the renal arteries. The histopathological hallmark in the wall of an AAA that distinguishes it from a saccular aortic aneurysm from syphilis is:
- A Obliterative endarteritis of the vasa vasorum with plasma cell infiltrate
- B Medial degeneration with elastic lamellae destruction and adventitial inflammation, predominantly neutrophilic ✓
- C Cystic medial necrosis with mucopolysaccharide accumulation
- D Destruction of elastic laminae with transmural neutrophilic vasculitis
Explanation
Atherosclerotic AAA shows medial thinning with destruction of elastic fibres and smooth muscle cells, adventitial and medial chronic inflammatory infiltrate (predominantly lymphocytes and macrophages driven by MMP-mediated matrix degradation), and overlying complicated atherosclerotic plaques. Syphilitic (luetic) aortitis characteristically shows obliterative endarteritis of the vasa vasorum with a surrounding plasma cell-rich infiltrate leading to ischaemic medial necrosis and saccular thoracic aortic aneurysm. Cystic medial necrosis (Erdheim's medial necrosis) is associated with Marfan syndrome.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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