Melanoma is a malignant skin tumour arising from melanocytes, the cells that produce melanin. It is a potentially aggressive cancer, often with rapid growth and a risk of metastasis if not diagnosed and treated at an early stage. It most commonly appears on the skin, but can also involve mucous membranes and the eyes.
Excessive, unprotected sun exposure, repeated sunburns in childhood or adolescence, tanning beds, fair skin type, family history of melanoma or other skin cancers, the presence of many moles or atypical nevi and certain conditions of immunosuppression all increase the risk.