WHAT IS MELANOMA OF THE SKIN?
Melanoma is the most dangerous malignant tumour of the skin and mucous membranes. It occurs due to malignant changes of cells called melanocytes. The cause of the occurrence of melanoma is still not fully known; apart from genetic influence there is also the connection of the occurrence of melanoma and ultraviolet (UV) radiation. Emphasized in particular is the connection of skin burns caused by excessive UV radiation in early childhood and later the occurrence of melanoma and intermittent exposure to UV radiation. Melanoma occurs more often in adults, the most commonly in the fourth decade of life, but can occur at any age, and then it is often associated with heritage. The occurrence of melanoma is also related with the number of moles and their clinical and dermoscopic appearance.
WHY DOES MELANOMA OCCUR?
In the occurrence of melanoma, the characteristics of the host are important (family inclination towards melanoma, previously diagnosed melanoma, number of moles, type of moles, skin type, gene mutations and the use of immunosuppressive drugs) and the environment (UV radiation). In the earliest stage of the development of melanoma, there is an uncontrolled duplication of melanocytes, changing their structure and differentiation. If the tumour is detected at this early stage, while the tumour cells did not pass the basal membrane, and is removed with an operational procedure, the ability to for the melanoma to continue to make progress and to further expand is minimum. When tumour cells penetrate the basal membrane and expand vertically and/or radially in the papillary part of the dermis, then it is an invasive stage of growth. With the further expansion of tumour cells, there is the spread of disease through the lymph vessels to the lymph nodes and through the blood.
Important risk factors in the occurrence of melanoma are:
- skin type: more common in people with light skin colour, hair and eyes (skin type I and II according to Fitzpatrick, see table 1)
- sunburn in childhood
- frequent use of tanning beds, especially in persons younger than 18 years of age
- positive family history
- a higher number of moles (moles that are atypical and congenital moles)
- immunosuppressed patients (patients with transplanted organs and hematological malignancies)