Coronary heart disease. A, Fibrous plaque from a 65-year old white male showing lipid-laden smooth muscle cells (SMCs) (short arrows). Cells vary greatly in size and some appear to be coalescing (long arrows). The SMC nucleus is flattened against the side of the lacunar space (open arrows). B, High-power view of the subendothelial area from A. Foam cells (white arrows) have formed beneath the endothelium and lumen (asterisk). Two large, lipid-filled spaces likely formed by the joining of adjacent SMCs that are now dead (black arrows). C, Micrograph of a coronary artery cross-section narrowed by a plaque. Images A and B courtesy of ncbi.nlm.nih.gov. Image C courtesy of genome.gov.