Morphological diagnosis of skin melanoma

The morphological diagnosis of melanoma is difficult and requires knowledge and evaluation of a large number of histological parameters and often immunohistochemical analysis proving the origin of the tumor. According to the latest WHO classification of skin tumors, melanoma is presented in its full variety of forms, with extensive characteristics of each, based on several key indicators: growth pattern, ultraviolet exposure/solar trauma and genetic disorders. Based on the presence or absence of radial growth, melanomas are divided into nodular, superficially progressive (pagetoid), and lentigo maligna melanoma. Depending on the involvement of solar trauma, they are divided into melanomas occurring in skin exposed to sunlight and cumulative solar trauma and those whose genesis does not involve solar trauma. The first group, developing in solar-exposed skin, includes melanomas associated with sun exposure in predisposed individuals. Clinically and histologically, they are associated with varying degrees of cumulative solar trauma. The second group, whose genesis does not involve solar trauma and ultraviolet radiation, are Spitz melanoma, acral melanoma, mucosal melanoma, melanoma arising on the basis of congenital nevus, melanoma arising on the basis of blue nevus, and uveal melanoma