The skin epithelium is structurally multilayered, keratinizing, and the cells forming it are called keratinocytes. The multilayered keratinizing epithelium consists of several layers of cells lying on top of each other. Moreover, the cells of the outer layer located on the surface gradually die off, turning into horny scales that peel off and are removed from the surface of the skin when washing. When the scales peel off, new epithelial cells rise in their place from deeper layers, which themselves begin to die off after a while and turn into scales. Thus, there is a process of constant renewal of skin epithelial cells – the surface ones die and peel off, and others that were previously in the underlying layer take their place. On the basement membrane of the epithelium, in turn, new epithelial cells are constantly forming, which gradually move towards the surface to eventually become scales and peel off. Normally, the rate of formation of new cells on the basement membrane and peeling of horny scales is balanced. That is, only the number of cells that are needed to replace those that have turned into horny scales is formed again. If the processes of exfoliation of scales and the formation of new epithelial cells are not balanced, this leads to the development of various skin diseases. This is how they are formed. Keratoma is formed from unchanged skin epithelial cells prone to excessive keratinization. That is, the tumor consists of a large number of ordinary keratinocytes – exactly the same cells that form the normal layers of the epithelium. Since keratomas are formed from normal cells, they are classified as benign tumors. However, keratomas are prone to degeneration into cancer. According to statistics, keratoma malignancy occurs in 8-20% of cases, depending on the type of tumor, the general condition of the human body, as well as the presence of negative factors contributing to the formation of cancer cells. Any keratoma at the initial stage looks like a slightly protruding spot above the skin, colored in gray or coffee colors. The surface of keratomas, as a rule, flakes off, which occurs due to the formation and peeling of a large number of horny scales. As the keratoma develops, the area of the keratoma increases, and the spot begins to protrude more strongly above the surface of the skin. On sufficiently large keratomas, a dense crust of horny scales forms, which can be torn off accidentally or intentionally. When a keratoma is traumatized, it can bleed and hurt, causing unpleasant sensations to a person.