Malignant Skin Tumours

Among the malignant tumours that can affect the epidermis and the adjacent mucous membranes are basal cell carcinomas (basaloma), squamous cell carcinomas (epitheliomas) and malignant melanomas.

Out of every 100,000 inhabitants in Western Europe, 20 people a year contract basal cell carcinoma, 12 people squamous cell carcinoma, and 14 people malignant melanom. In sunny countries such as Australia and the southern states of the USA, the number of people who suffer these kind of tumours is ten to twenty times higher. Altogether, the number of cases, especially of melanomas, has been increasing dramatically. Since 1970, the incidence has nearly doubled every 10 years. It is currently estimated that 1 in every 75 inhabitants of America will contract melanoma.

The most common age at which people contract basal cell carcinoma and squamous cell carcinoma is between 60 and 80; malignant melanoma tends to affect people in their middle years.

In Western Europe, basal cell carcinoma affects both sexes equally. In the case of squamous cell carcinoma, men tend to suffer twice as frequently as women, while malignant melanoma affects women more often than men. In very sunny countries, males are 20 – 100 % more likely to contract basal cell carcinoma than women and 2 to 3 times more likely to suffer squamous cell carcinoma than women. Malignant melanoma, on the other hand, has been found to affect both sexes equally.

The goal of all information on this topic must be to enable malignant tumours of the skin, which are, after all, “visible”, to be discovered and treated in the early stages. If diagnosed and treated early enough, all skin cancers are curable!

Basal cell carcinoma

Basal cell carcinoma, also known as basaloma, is the most common form of malignant skin tumour. It develops out of the basal cells of the epidermis, is usually only aggressive and destructive in a localised area, and almost never forms metastases (i.e. it does not scatter and form cancers in other parts of the body). Because of the locally destructive growth, the basaloma has to be treated radically as otherwise it grows into the surrounding skin, subcutaneous fat, cartilage and bone structures.

Basalzellkarzinom

Fair-skinned, sun-sensitive people (skin types I and II) produce less protective pigment (melanin) and are therefore at greater risk of contracting basaloma. The most important risk factor, however, is chronic light exposure of the skin throughout life. Unlike malignant melanoma, sunburn is not the main predisposing factor, but the aggregate exposure of the skin to sunlight. Another cause of basaloma used to be the treatment of psoriasis or other skin conditions with tinctures containing arsenic, as well as the use of arsenic-based sprays in wine growing. Decades after exposure to these substances, people frequently contracted basalomas or other skin tumours such as actinic keratosis, Bowen’s disease and squamous cell carcinoma.

Basal cell carcinomas can have different forms of growth. A frequent form in the facial region are shiny, skin-coloured nodules with conspicuously enlarged blood vessels. The tumours also frequently become ulcerous in the middle, and then form a scab. Other basalomas are flat, i.e. level with the skin, reddish in colour, slightly scaly, and have a shiny margin. Occasionally, they may also have a darkish brown pigmentation.

As they do not form metastases, it is usually sufficient for basalomas to be removed surgically, together with a sufficient area of the surrounding tissue, followed by regular check-ups. In special localities or for people of advanced age, they may also be treated with X-rays.

Squamous cell carcinoma

Squamous cell carcinoma (epithelioma, acanthoma) is a malignant tumour that starts from the prickle cells of the epidermis. It can occur both on the normal skin and also on the mucous membranes. For the normal skin, chronic exposure to sunlight is a major causal factor. But also X-rays as well as exposure to various chemicals such as arsenic, polycyclical hydrocarbons, pitch, tar, crude, heating and lubricating oil, tobacco and soot can promote the development of squamous cell carcinomas. Tumour growth on the mucous membranes of the oral cavity is fostered by alcohol in combination with chronic nicotine abuse, and on the mucous membranes of the genitals by chronic viral infections.

Especially on the normal skin, squamous cell carcinomas frequently develop from pre-cancerous skin conditions. These include actinic keratosis and Bowen’s disease. Both these pre-cancerous forms occur only on the skin and do not form metastases. However, they do not heal spontaneously either and should therefore be treated.

Squamous cell carcinomas predominantly develop on skin which has previously suffered severe light exposure, i.e. the cheeks, nose, lips, the upper edges of the ears, the backs of the hands and the outside of the forearms, and less commonly on the trunk and lower legs and, in the case of men, on the bald patches of the scalp. On the lower legs, they frequently develop out of chronic ulcers.

Squamous cell carcinomas can be reddish, yellowish or skin-coloured, and they always start as a small, painless, hard nodule, which with increased growth may become ulcerous and be covered with a scab. In the early stages, they are often only a red spot with firmly adhering scales. On the mucous membranes, e.g. the lips or genitals, squamous cell carcinomas begin with whitish coloured hardening of the skin or dark red, sharply delineated, slightly hardened discolorations. Squamous cell carcinomas that grow invasively break through the basal cell layer and into deeper skin regions like the dermis, and have the ability to form metastases. Normally, this first affects the regional lymphatic nodes, but can then also spread to the lungs.

Treatment of these carcinomas is usually done by surgery, though in rare cases also by radiology. The pre-stages of squamous cell carcinomas (actinic keratosis and Bowen’s disease) can also be treated with cryotherapy (liquid nitrogen) or fluorouracil, a local cytostatic.

Malignant melanoma

Malignant melanoma is the most malignant form of skin cancer. Malignant melanomas normally affect people with white skin (Caucasians). 30 % of malignant melanomas occur on pre-existing, pigmented skin changes, or “moles”, and 70 % on normal skin without any such pre-stages.

In women, they predominantly occur on the face and legs, in men on the upper trunk.

malignes-melanom

There are 4 types of melanomas. The most common is the superficially spreading melanoma, which accounts for 65 % of all cases. The expression “superficially spreading” refers to the growth phase. These tumours initially grow sideways in the epidermis (basal cell layer); only after several months or even years do they then break out of the basal cell layer and grow down into the dermis. Clinically, the tumour can be recognised by irregular, mottled pigmentation, curved branching at the edges, and changes to the surface structure of the skin.

The nodular melanoma (20 % of melanomas) is usually deep black in colour, but can occasionally also be skin coloured or even reddish. With this type, there is no superficial growth phase; it immediately penetrates downwards into the skin, lessening the chances of successful treatment.

The lentigo malignant melanoma (10 % of melanomas) initially grows superficially in the epidermis – and usually more slowly than the other types of melanoma. Irregularly shaped patches of blackish or brown-grey colour may exist for many years in areas of the skin that are chronically exposed to light – especially the face. Unlike the other types of melanoma, chronic light exposure – at least, as far as is known today – is more important for the occurrence of lentigo malignant melanoma than the number of sunburns.

The acrolentiginous malignant melanoma (5 % of melanomas) occurs in the places indicated by the name, i.e. on the hands and feet. These melanomas often have an irregular brown-black pigmentation, but can also be reddish or colourless, and frequently also involve the nail structures. Every pigment spot on the nails which is not clearly due to an injury or bleeding should therefore be carefully examined.

In the case of all malignant melanomas, early detection is crucial because these tumours already cause metastases at an early stage, which makes the chances of successful treatment very poor. The ABCDE rule is a good guide for early detection.

All irregularly shaped, very dark or mottled, multi-coloured pigment spots on the skin are suspicious and must be examined by a doctor.

Therapy is done in the form of radical excision, with the malignant melanoma being removed as a whole together with a surrounding safety zone. The size of the safety zone depends on the thickness of the tumour. The thicker the tumour is, i.e. the deeper it has grown down into the deeper skin structures, the higher the risk that it has formed metastases. The reason for this is that once the tumour has broken through the basal membrane, it can gain access to the blood and lymphatic vessels. The deeper it penetrates into the dermis, the more blood and lymphatic vessels there are. The thickness and penetration level of the tumour are identified in examination of the tissue under the microscope, and are crucial for the healing prognosis. In the case of thicker tumours, the sentinel lymph node is today also removed. The sentinel lymph node is the first lymph node that lies in the path of lymph outflow of the tumour. If this lymph node is also affected, the whole lymph node station is removed. In the case of high-risk malignant melanomas, surgery is often followed by immune stimulation therapy using interferon.

As already described in the chapter “The sun and skin”, the best protection against malignant skin tumours and light ageing is sensible exposure to sunlight and the use of sun protection products. The long latency period of several decades which can go by before skin tumours and sunlight-induced skin ageing occurs is deceptive and often delays the timely use of sun protection products. These should be used consistently from babyhood on. The earlier the use of these products begins, the better the protection against light damage to the skin. The general opinion today is that up to 80 % of all long-term damage to the skin is sustained by the time people have reached the age of 20.

Note: It is not the sun that causes illness, but our underestimation of its effects!