Melanoma malignum is a malignant tumor that origins from the pigmented cells (melanocytes) in the skin. Its etiology is still unknown. Even the histological origin of the melanocytes is not clear and scientists are not sure whether melanocytes originate from the nerves or epithelial tissue. Melanoma can occur wherever melanocytes are present (especially in the skin or eye). Melanoma usually develops from a benign nevus on the skin. Sometimes, melanoma can even originate from completely healthy skin. Melanoma is not connected with the other types of cancers.