Melanoma: a kind of tumor, mainly distributed on the surface of the skin, so it is also a pre-symptom of skin cancer, with a high mortality rate, it should be diagnosed and treated in time.

Melanoma is a malignant tumor originating from melanocytes in the pigmented areas of the skin, mucous membranes, eyes and central nervous system.

Most malignant melanomas originate from melanocytes in normal skin, with approximately 40% to 50% occurring in pigmented nevi (see Section 125, Nevi and dysplastic nevi). Malignant melanoma is rare in children but can arise from very large pigmented nevi that are present at birth. Halo nevi usually disappear on their own but in rare cases become melanomas. Although pregnancy predisposes to melanoma, pregnancy does not increase the likelihood that a nevus will turn into a melanoma. Moles often change in shape and size during pregnancy. The following danger signs indicate that a nevus is becoming malignant: change in size, change in color, red, white, or blue, especially if the area of hyperpigmentation spreads to the surrounding normal skin; change in surface features, change in texture and shape; and inflammation of the skin around the nevus in particular, which may be manifested by bleeding, ulcers, itching, or pain.