Melanoma is a type of skin cancer that begins in melanocytes, the skin cells that produce melanin, which gives skin its color. It is also called malignant melanoma and cutaneous melanoma. Exposure to ultraviolet (UV) rays from the sun is a major cause, but with early detection and treatment, the survival rate is extremely high.
Melanoma: learn more
Melanoma is much less common than other types of skin cancers, like squamous cell carcinoma and basal cell carcinoma. If not detected and treated early, melanoma can be dangerous because it’s much more likely to spread to other parts of the body.
A melanoma typically presents as looking like a mole—in fact, an existing mole can become a melanoma. They can develop anywhere, but they typically start on the neck and face, on the trunk chest and back in men, and on the legs in women. They can also form in other parts of your body, like the eyes, mouth, genitals and anal area, but these are much less common than melanoma of the skin.
Most melanoma cells still make melanin, so melanoma tumors typically present as brown or black. Some melanomas do not make melanin, so they can appear pink, tan or even white.
Types of melanomas
Superficial spreading melanoma. About 70% of all cases.
Lentigo maligna. Occurs most often in the elderly on chronically sun-exposed skin on the face, ears, arms and upper trunk.
Acral lentiginous melanoma. Presents as a black or brown discoloration under the nails or on the soles of the feet or palms of the hands.
Nodular melanoma. Usually invasive at diagnosis, appearing as a black bump.
Desmoplastic melanoma. Presents as a slowly enlargening area of thickened skin, sometimes seen as ill-defined scar-like lesions.
We know that UV rays are a major cause of melanoma, as they can cause genetic mutations that turn cells into cancer. There are other risk factors to watch for as well.
Acquired gene mutations. Some genetic changes occur over a person’s lifetime, and are not inherited. We know that UV rays can damage DNA in skin cells, changing how they grow and divide. Most UV rays come from sunlight, but some can come from man-made sources such as tanning beds. The most common change in melanoma cells is a mutation in the BRAF oncogene, which is found in about half of all melanomas. Some melanomas occur in parts of the body that are rarely exposed to sunlight, which have different gene changes.
Inherited gene mutations. Sometimes people do inherit gene changes that raise their risk of melanoma, such as those with xeroderma pigmentosum (XP).
These can make a person more likely to develop melanoma:
- UV light exposure. Sunlight is the main source, and tanning beds and sun lamps are also sources.
- Moles. A mole is actually a benign (non-cancerous) pigmented tumor.
- Having many moles. Most moles will never cause any problems, but someone who has many moles is more likely to develop melanoma.
- Atypical moles (dysplastic nevi). These moles look like normal moles but also have some features of melanoma.
- Dysplastic nevus syndrome (atypical mole syndrome). People with this inherited condition have many dysplastic nevi and have a very high lifetime risk of melanoma, so they need to have very thorough, regular skin exams by a dermatologist.
- Congenital melanocytic nevi. Moles present at birth.
- Fair skin, freckling, and light hair. The risk of melanoma is much higher for whites than for African Americans.
- Family history of melanoma.
- Personal history of melanoma or other skin cancers.
- Having a weakened immune system.
- Being older. Melanoma is more likely to occur in older people, but it is also found in younger people.
- Being male.
- Xeroderma pigmentosum. A rare, inherited condition that affects skin cells’ ability to repair damage to their DNA.