CUTANEOUS HORN is a rare tumor–like
formation of horn
cells. It can occur
independently or as
a result of other benign
formations (warts, papillomas)
or malignant
genesis (RCC). Both
internal (endocrine pathology,
tumors, viral infection)
and external
(ultraviolet radiation, trauma)
factors can provoke
the development of such a process.
Clinically, it is most often manifested
by a single cone-shaped
horny element
with clear
boundaries, dense, indeterminately
dark in color, with
a smooth or striated
surface, and an erythematous inflammatory rim around
the base. Less often, the process becomes
widespread. It is localized mainly
on the skin, rarely
on the mucous membranes.
It is believed that such a powerful proliferation of the epidermis is based on a violation of cellular kinetics, which consists of several components: a sharp acceleration of mitotic cell division, accelerated migration to the skin surface of cells overflowing with keratin, acceleration of genetically programmed physiological cell death.
The essence of the changes in the skin layers in this case is the proliferation of the spiny, granular and horny layers of the epidermis, which become loose, the number of desmosomes (intercellular contacts) increases in them, which have lost contact with tonofilaments (protein filaments of the desmosome framework and keratinocyte cytoplasm), "soft" zones appear, available for "pushing through" their dermis. The adjacent unchanged areas of the epidermis are compensatorily embedded in the thickness of the dermis. This creates a solid foundation for horn formation. In the future, more and more new products of disrupted cellular kinetics are layered on this platform.
There are two types of the disease:
It is believed that such a powerful proliferation of the epidermis is based on a violation of cellular kinetics, which consists of several components: a sharp acceleration of mitotic cell division, accelerated migration to the skin surface of cells overflowing with keratin, acceleration of genetically programmed physiological cell death.
The essence of the changes in the skin layers in this case is the proliferation of the spiny, granular and horny layers of the epidermis, which become loose, the number of desmosomes (intercellular contacts) increases in them, which have lost contact with tonofilaments (protein filaments of the desmosome framework and keratinocyte cytoplasm), "soft" zones appear, available for "pushing through" their dermis. The adjacent unchanged areas of the epidermis are compensatorily embedded in the thickness of the dermis. This creates a solid foundation for horn formation. In the future, more and more new products of disrupted cellular kinetics are layered on this platform.
There are two types of the disease:
- Primary or benign – it appears on the skin spontaneously, the causes are unknown, the course is benign, there is no component of inflammation.
- Secondary (false) or malignant is a consequence of the transformation of the primary formation as a result of exogenous-endogenous causes with the development of an inflammatory process at the base of the horn. This is the most dangerous type of pathology, it is prone to rapid malignancy of the process.