Atheromatosis

Atheromatosis (from Greek athera- porridge), represents a pathological change of tissues, reducing to the appearance in them of foci of decay, consisting of a pasty mass of fatty substances, cholesterol crystals, lime salts and the like. Foci of atheromatous decay are encountered especially often in the inner lining of arteries during sharply expressed atherosclerosis (see Atherosclerosis). Ulcerating, atheromatous foci open into the lumen of the arteries, forming atheromatous ulcers. The latter are often covered by mural thrombi. The development of foci of atheromatous decay is explained, mainly, by the deposition here in the intermediate tissue of a large amount of lipoid substances and, in particular, cholesterol, during sharply expressed atherosclerosis. The deposition of lime in such foci occurs secondarily, mainly, thanks to the decomposition of cholesterol esters with the formation of fatty acids and their successive connection with the lime salts of the plasma. Besides the walls of the arteries, A. is encountered often in other parts of the organism, where there is an accumulation of dense fibro-elastic tissue, for example, in the valves of the heart, tendons and the like. Around the circumference of atheromatous decay are observed usually quite sluggish reactive changes, for example, in the form of accumulation of wandering cells, absorbing lipoids and transforming into the so-called xanthomatous cells. The etiological moments leading to atheromatosis are the same as with atherosclerosis, i.e. consist, mainly, in a disorder of lipoid metabolism on the one hand, and in local mechanical influences, on the other.