The 'vulnerable' atherosclerotic plaque most prone to rupture and acute thrombosis is characterized by:
- A A thick fibrous cap with a small lipid core and abundant smooth muscle cells
- B A thin fibrous cap (<65 microns), a large necrotic lipid core, and abundant macrophage foam cells with paucity of smooth muscle cells ✓
- C Heavy calcification throughout the plaque with no inflammatory cells
- D Intraplaque hemorrhage from the lumen directly into the calcified core
Correct answer: B. A thin fibrous cap (<65 microns), a large necrotic lipid core, and abundant macrophage foam cells with paucity of smooth muscle cells
Explanation
Vulnerable (rupture-prone) plaques have a thin fibrous cap (<65 µm), a large necrotic lipid-rich core, abundant macrophages (which secrete matrix metalloproteinases degrading collagen), and few smooth muscle cells. Rupture exposes the thrombogenic lipid core and subendothelial collagen to blood, triggering acute coronary syndromes. Heavily calcified stable plaques are less prone to rupture.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.