It can be considered that tumours derived from melanocytes are among the commonest tumours occurring in humans. Most of them are benign but they sometimes can become malignant melanomas, that is, very aggressive tumours [2, 3].

Melanoma is the skin tumour with the lowest incidence. Yet its relevance lies mainly in two facts: its high lethality and its relatively high incidence among younger cohorts. Moreover, this tumour has recently received substantial attention because of the increase in its incidence, which has been registered in many countries world-wide [4].