Hyperchromatosis

HYPERCHROMATOSIS (from Greek hyper- excessively and chroma- coloration), excessive content of chromatin (staining substance) in cell nuclei. The ratio of staining and non-staining (chromatic and achromatic) substance varies in different cell forms. In most cells (epithelium, adipose tissue, loose connective tissue, etc.), chromatin is located in nuclei in the form of a delicate network or small granules. In other cases, chromatin particles, merging together, accumulate in a continuous or interrupted in many places thick layer on the inner surface of the nuclear membrane (Maximov). This arrangement of chromatin is characteristic of red blood cells in various generations of their development, and in normoblasts it appears as diffuse, almost solid staining of the nucleus. To a greater or lesser degree, hyperchromatosis is also expressed in other types of cells (smooth muscles, bone cells, etc.), but it can also occur in those cells to which such a nuclear structure is generally not inherent, for example, in epithelium, where this state of chromatin indicates accelerated multiplication of these cells (during regeneration). Hyperchromatosis is very often found in various tumors with rapidly progressing cell multiplication. In atypical, multipolar mitoses, different states of chromatin can often be observed in daughter nuclei. Hyperchromatosis should not be confused with nuclear pyknosis, which occurs in the so-called degenerative and necrobiotic processes in them.