A fibroatheroma is an advanced atherosclerotic plaque characterised by a lipid-rich necrotic core covered by a fibrous cap within the arterial wall. It is clinically significant because its structural integrity influences the risk of plaque rupture, which can precipitate acute coronary syndromes. A thin fibrous cap overlying a large necrotic core is particularly prone to rupture, leading to thrombosis and myocardial infarction.