The skin is the largest organ of the human body and one of its most important functions is to protect the body’s internal structures from harmful environmental factors. The skin is the first barrier to micro-organisms, the sun’s UV rays and other harmful factors in the external environment. In addition to these, there are other equally important functions of the skin, such as the production of vitamin D, sensory and thermoregulation, maintenance of water and electrolyte balance, removal of metabolic products, and absorption of substances (e.g. externally administered drugs).
The skin has 3 main layers:
- The epidermis, made up of keratinocytes. The epidermis is separated from the actual skin by a structure called the basement membrane. In a normal case, the epidermis regenerates on average within 26-28 days. The epidermis also contains other cells such as melanocytes and immune cells.
- Dermis (real skin). It consists of connective tissue, elastic, collagenous and reticular fibres, including blood vessels, nerves and various cells. In addition, the dermis is where sweat and sebaceous glands and hair follicles are located.
- Podium. This is the fatty tissue, which is divided into smaller lobules by connective tissue septae.
The above-mentioned structural and functional features of the skin account for the wide variety of skin tumours. Basically, all skin neoplasms are divided into 3 main groups:
- Benign lesions
- Skin cancers
- Pre-cancerous conditions
Benign skin tumours are a very heterogeneous group of skin lesions. They differ in their cause, symptoms, treatment methods, etc. Every person has benign skin tumours and they continue to be acquired over the course of life. These include warts, moles, skin papillomas, dermatofibromas, seborrhoeic keratoses (“senile warts”), haemangiomas, lipomas, etc. For example, warts are caused by human papillomavirus infection, seborrhoeic keratoses are caused by age-related changes in the skin and exposure to harmful UV rays, and lipomas are simply a formation of fat cells in the subcutaneous tissue, confined to the capsule.
In rare cases, benign skin tumours may visually resemble skin cancer. Therefore, if any new suspicious skin lesion appears, do not hesitate to consult a dermatologist.
Benign skin lesions do not pose a health risk and are removed at the patient’s request for better cosmetic results. For more information, see “Benign skin tumours”, “Removal of benign skin tumours”.
Malignant skin tumours are classified according to the origin of the skin cells:
I. Non-pigmented (epithelial, non-melanoma) tumours:
- Basalioma (basal cell carcinoma)
- Squamous cell carcinoma
II. Pigmented tumours of melanocytic origin:
Non-pigmented skin tumours account for the majority of all skin cancers. Basalioma is the most commonly diagnosed malignant skin tumour, followed by squamous cell carcinoma, which accounts for up to 20% of all skin cancers. Melanoma, although a rarer form of skin cancer, is the most aggressive and, if diagnosed late, has the worst prognosis for survival. According to the Lithuanian Cancer Registry, around 200 cases of melanoma are diagnosed each year, two thirds of them in women. The incidence of melanoma has started to increase rapidly. By comparison, in 1935, the odds of developing melanoma were 1 in 1500, and in 2000 they were already 1 in 75. The increased incidence is mainly due to increased life expectancy, increased time spent in the sun (and thus increased sunburn), use of sunbeds and changes in the environmental ecology.
Early and timely diagnosis of skin cancer significantly reduces the risk of the disease spreading and improves survival. Skin tumour screening is a simple, painless and quick process. In addition, early-stage disease is much easier to treat.
The main method of treating skin cancer is surgical removal of the mass. In 90% of cases, this is done on an outpatient basis, under local anaesthesia, so the patient can go home the same day.
Pre-cancerous skin cancers occupy an intermediate stage between benign and malignant skin lesions. Histological examination (i.e. microscopic examination of a tumour fragment) reveals atypia of the cells that make up the lesion – certain structural changes that healthy cells do not have, but which are not a sign of cancer. However, a precancerous skin lesion is more likely to develop into skin cancer later in life. The main pre-cancerous skin conditions:
- Actinic keratosis
- Atypical moles
After the diagnosis of a pre-cancerous skin lesion and an assessment of the patient’s condition, treatment and active surveillance are prescribed. For more information, see the section “Pre-cancerous skin conditions”.