Which nuclear change is characterized by small, dark, condensed nuclei?

The correct choice is pyknosis, which refers to a specific type of nuclear change observed in dying cells. Pyknosis is characterized by the shrinkage and condensation of the nucleus, leading to a more intensely stained, darker appearance when observed under the microscope. This phenomenon occurs as the chromatin within the nucleus condenses tightly, resulting in nuclei that appear small and dark.

This process often indicates that the cell is undergoing necrosis or apoptosis, suggesting that the cell is in a state of irreversible damage or intentional self-destruction. Understanding pyknosis is essential for pathologists as it helps to identify the fate of cells in diseased tissues.

In contrast, karyorrhexis describes the fragmentation of the nucleus, which usually presents as irregularly sized and shaped parts of the nuclear material, while karyolysis is the dissolution of the nucleus due to enzymatic activity leading to a more pale or ghost-like appearance. Anisokaryosis refers to a variation in nuclear sizes within a cell population, rather than a specific change in individual nuclei. Recognizing these distinctions is critical for accurate cytological assessment and diagnosis.