Aortic Atherosclerosis
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These light micrographs show a human aorta with atherosclerosis (Grade IV of the American Heart Association). The top image is a Hematoxylin and Eosin stained slide and the lower image is stained with a Movat pentachrome stain. The layers are labeled at low magnification as follows: 1. Atheromatous plaque; 2. Media; 3. Adventitia. The atheromatous plaque shows several components. The topmost layer is a continuous fibrous tissue plaque (yellow in the Movat stain) which spans all across the field of this atheromatous plaque. Subjacent to the fibrous tissue plaque there are areas of atheroma (lipid core), where the empty unstained “needle-like” spaces in both the H&E and the Movat stains represent clefts left over by dissolution of cholesterol during the processing of the tissue for the production of the microscopic glass slides. In between the areas of atheroma there is connective tissue rich in lipid-laden macrophages (pale foamy cells) flanking the atheroma. The media shows for the most part a parallel array of elastic lamellar units. The elastic lamellae are stained in black (in the Movat stain) and form undulating lines across the length of the media. The parallel array of the lamellar unit is interrupted in some areas, and in other areas there is distinct loss of continuity forming gaps, which are filled by green/yellow connective tissue. These particular changes are more conspicuous towards the left and right edges of the media in this sample. The adventitia is a yellow layer formed of fibrous tissue (predominantly collagens type I and III. Vasa vasorum and small nerves are present in this layer.
