Melanoma. Close-up of a malignant melanoma skin cancer. Melanomas are cancerous tumours of melanocytes, the cells that produce melanin (the pigment that colours the skin, hair and eyes). They usually occur in the skin, but may also appear in the eyes and mucous membranes. They usually contain melanin (as here), which gives them a dark colour, but they may also be free of pigment. Melanomas typically spread quickly to other parts of the body, which inevitably leads to death. If caught early, they may be removed surgically. Radiotherapy and chemotherapy may also be needed. This grade 3-4 superficial spreading melanoma measured 2mm on the Breslow Indice.