Amyloid Bodies

AMYLOID BODIES (corpora amylacea, literally translated as starch-like bodies) are usually microscopically small, rounded, homogeneous or, more frequently, concentrically laminated bodies resembling starch grains. Because these bodies sometimes yield a reaction similar to that of amyloid (see Amyloid Degeneration) when treated with iodine and aniline dyes, amyloid bodies were formerly identified with the latter; subsequently, however, it was established that amyloid bodies have nothing in common with amyloid, either in their chemistry or in their mode of formation. Amyloid bodies are most frequently found in the glandular acini of the prostate gland and in the central nervous system, appearing and increasing in number in these organs with age; in addition, they are observed in the pulmonary alveoli (more often in chronic inflammation), in the connective tissue of chronically inflamed skin (in elephantiasis), in the mucosa of the urinary tract, and in various types of cysts. At present, there is no doubt that the term amyloid bodies groups together rounded, laminated bodies that are highly diverse in their chemistry and mode of formation. Thus, the amyloid bodies of the prostate gland, which are sometimes visible to the naked eye on a section of the organ as brown granules due to their size, arise in connection with the death and disintegration of epithelial cells; the amyloid bodies of the central nervous system, which are microscopically small, are formed, according to some, from the disintegrating axis cylinders and myelin of nerve fibers, according to others, from degenerated neuroglia cells, and according to a third view, as a result of the precipitation of metabolic products; the origin of amyloid bodies in the lungs is associated with the deposition of the breakdown products of dying leukocytes or condensing exudate around a foreign body (for example, a coal particle). On the basis of microchemical reactions, Siegert divides amyloid bodies into two main groups: 1) corpora versicolorata (variegated bodies) and 2) corpora flava (yellow bodies). However, this subdivision is now considered insufficient and not entirely correct; for example, amyloid bodies with the properties of both corpora versicolorata and corpora flava are found in the prostate gland, and it is likely that their microchemical properties can change depending on the duration of their formation. Amyloid bodies have no special pathological significance and do not themselves cause any changes in the tissues; only in rare cases do they acquire the significance of foreign bodies, and giant cells that resorb them appear around them.