Definition of a basal cell carcinoma
A basal cell carcinoma is a certain type of skin cancer. This (semi) – malignant tumour originates from the so-called basal cells of the epidermis. It is usually caused by intensive solar radiation. Basaliomas occur in 80 percent of the face – neck – area. Metastases (daughter tumours) are extremely rare, which is why it is classified as semi-malignant, i.e. semi-malignant.
Early stage of the basal cell carcinoma
It is a skin tumour that develops from the basal cells of the epidermis. The tumour does not form any daughter tumours, so-called metastases. This skin tumour is therefore called semi-malignant.
In the early stages, the tumour is usually not noticed at all or is merely mistaken for an unevenness in the skin. In the beginning, small greyish, glassy nodules usually develop, which are slightly shiny and look like papules. Often small winding blood vessels are already visible on the surface and at the edges (telangiectasia).
Typical for a basal cell carcinoma is also a so-called edge wall, which arranges itself like a string of pearls around the nodule. By scratching or after shaving, crusts can form on the nodules, which now and then start to bleed easily. In the early stages, the tumour is always limited to the skin.
After months or years the surface of the nodule sinks in the middle, so that a small central dent is formed. Starting from this dent, the tumour starts to attack the deeper lying tissue as well as the surrounding cartilage and bone structures, grows into them and destroys them. Therefore, new skin changes should be carefully observed.
Occurrence in the population In the fair-skinned population, the basal cell carcinoma is the most frequent malignant skin tumour with about 80,000 new cases per year. Depending on the geographical location, these tumours occur more or less frequently. In Central Europe, for example, about 60 per 100,000 inhabitants are affected, while in Australia 250 per 100,000 inhabitants suffer from this form of skin cancer.
In recent years, the frequency has increased steadily. Men are slightly more likely than women to get the disease. As mentioned above, basaliomas develop from the basal layer of the epidermis.
This layer contains so-called basal cells. These cells normally divide several times before they are transported into the upper cell layers of the epidermis (upper layer of the skin). Here they lose their ability to divide and become horny.
A basal cell carcinoma now develops from such a degenerated basal cell. In contrast to the healthy basal cell, this cell does not keratinize in the uppermost layers of the epidermis. It does not possess this ability.
Instead, it can divide further. Although the risk factors for the development of skin cancer are largely known, the mechanism of tumor development is not completely clear. The main risk factor for the development of basal cell carcinoma is chronic, intensive solar radiation.
Persons with light and sun-sensitive skin are particularly affected. In most cases they develop in places that are often and frequently exposed to the sun. Besides UV radiation, chemicals (e.g. arsenic) also play a role.
Physically, burns and X-rays can be dangerous. A genetic predisposition to the formation of basaliomas may also be present. In this case a gene mutation is present, which allows malignant basaliomas to develop from initially benign tumours after puberty.
This disease is called Gorlin – Goltz – Syndrome. In rare cases, this type of skin cancer can also develop from chronic wounds. The basalioma usually grows very slowly.
However, they are clearly visible on the skin, but are often not noticed. The original basal cell carcinoma is a nodule about the size of a pinhead, skin-coloured and rough. Typical is the pearl-like wall at the edge.
Just as typical are the small vessels that grow into the tumour and feed it (telangiectasia). As a result, the tumour appears reddishly shimmering through. In a later stage, the tumour tends to grow inwards and decays.
Outside the face, basal cell carcinoma can resemble a rash (eczema) with redness and scales. There are different types of basal cell carcinoma. Their manifestations range from flat to knotty to ulcerous.
Flat and nodular forms show a pearl-like border wall and small ingrown vessels (telangiectasia). Ulcer-like basaliomas are reminiscent of a non-healing graze. Basaliomas do not originally occur on the mucous membranes, but can grow into them.
Basaliomas can also grow into bone and cartilage. Especially if they are discovered late. This ingrowth usually leads to disfigurement because the basaliomas are mostly found on the face (lip margins, eyelids, nasal skeleton).
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