Karyopyknosis

Karyopyknosis is the process of compaction of chromatin in the cell nucleus. In karyopyknosis, chromatin gathers into small round clumps and acquires a basophilic color.

Karyopyknosis can be observed under normal and pathological conditions. It is one of the signs of apoptosis - programmed cell death. During apoptosis, chromatin in the nucleus condenses and fragments.

Karyopyknosis also occurs during necrosis - undirected pathological cell death. In this case, the nucleus decreases in size and acquires a homogeneous basophilic color.

Observation of karyopyknosis during histological examination may indicate the presence of pathological processes in the tissue.

Karyopyknosis is a nuclear atypia found in malignant tumor cells associated with an increase in chromatin density. Also called “hard nuclei” or in English “hard nuclei”. Described at the beginning of the 20th century simultaneously by G. Ginzburg and G. Kulchitsky. Unfortunately, I did not find detailed information about the time of discovery of this phenomenon, but there is evidence that karyopyknosis is so named because of the compacted chromatin composition.

Cells of a malignant nature often undergo karyotypic changes. The cells are characterized by rounded or rounded nuclei, stained dark blue with eosin, and when treated with methylene blue they acquire a characteristic blue color. Changes in nuclear color can also be detected with the naked eye: a dense nucleus may have a reddish-brown color due to DNA fragmentation. The karyotype spectrum indicates reproduction by mitosis. Most of the nuclei are located in the affected area in close contact with each other, leaving no room for extrameyolar cells.