The earliest lesion of atherosclerosis is the formation of lipid spots and streaks. The so-called lipid spots are small yellow dots that appear on the arterial intima. Under pathological observation, these are small areas of macrophages containing lipid droplets, forming a cluster of foam cells. As this small yellow dot develops, it gradually turns into a yellow streak made up of layers of macrophages containing lipids. The intima also comprises smooth muscle cells and lipids, as well as an infiltration of T cells, resembling a yellow streak on the intima.