From Big Medical Encyclopedia

DYSKERATOSIS (dyskeratosis; grech, dys-+ keras, kerat[os] a horn + - osis) — the disturbance of physiological process of keratinization which is expressed pathological keratinization of separate epidermal cells. Cells of epidermis become larger, roundish with intensively painted kernels and eosinophilic, slightly granular cytoplasm, seem double-circuit. Such cells are deprived of intercellular contacts therefore they drop out of the general communication (see. Acantolysis ), chaotically being located in all departments of epidermis. In process of advance of a knaruzha these cells gain spherical shape, in this regard. Darya (1930) gave them the name «corps ronds» — «round bodies» (or little bodies Darya). Cells then turn into the homogeneous, acidophilic educations with very small piknotichny kernels called by grains (grains) which are located in a corneous layer (fig. 1). G. M. Saralidze and T. A. Vartapetova (1966) noted reduction of a glycogen and RNA in round bodies and total absence of these ingredients in grains.

Fig. 1. Microdrug of epidermis at a high-quality dyskeratosis (a disease to Darya). Round bodies (1) and grains (2) in a corneous layer.
Fig. 2. The diffraction pattern of a round body from epidermis at a disease to Darya. The Piknotichny kernel (1) and the autolizirovanny site of cytoplasm (2) surround tonofibrils (3) in the form of rough bunches. Desmosomes are absent.

Disturbance of a complex of a tonofibril — a desmosome, expressed in dissolution of a contacting layer of desmosomes with the subsequent separation from them of tonofibrils which skoplyatsya around a kernel is the cornerstone of the Dyskeratosis. In round bodies of a tonofibril are located around a kernel in the form of the dense, keratinopodobny bunches surrounding destructively changed central part of cytoplasm (fig. 2). Further consolidation and reduction of quantity of a keratin in these cells with formation of empty zones leads to formation of grains.

Clinically distinguish two types of the Dyskeratosis — so-called high-quality and malignant. The high-quality Dyskeratosis is observed, for example, at a disease to Darya, and also at an infectious mollusk and is characterized by formation of round little bodies and grains. At a malignant Dyskeratosis occurs keratinizations of unripe and atypical cells that is especially characteristic of Bowen's disease; it can be observed at a senile keratosis, a planocellular carcinoma cutaneum and some precancerous diseases of skin.

The term «dyskeratosis» is applied also as the name of some diseases when process of keratinization, for example a follicular dyskeratosis (is broken see. to Darya disease ), etc. See also Keratinization .

G. M. Tsvetkova.