Understanding Melanoma: Causes, Symptoms and Treatments

Medically Reviewed by Kelsey Powell, MS, Medical Sciences

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Understanding Melanoma: Causes, Symptoms and Treatments

Melanoma is a type of skin cancer that develops in the skin cells (melanocytes) responsible for producing the pigment that gives your skin color (melanin). It’s usually caused by ultraviolet (UV) rays from the sun or tanning beds. With melanoma, melanocytes that have mutated — meaning they’ve undergone spontaneous changes that can make them harmful — multiply quickly. This rapid growth forms tumors in the epidermis, your skin's top layer, and the diseased cells can spread to other parts of your body without effective treatment.

Melanoma rates have been rising over the past few decades. According to the American Cancer Society, approximately 106,000 new cases are diagnosed each year in the United States alone. Melanoma is more prevalent in fair-skinned individuals, and white people are more than 20 times more likely to develop the disease than Black people. Melanoma is also more common in men. However, other factors can also influence an individual’s risk of developing the disease.  

Melanoma isn’t the most common type of skin cancer; however, it does have the highest death and metastasis (meaning it’s moved to different areas of your body) rates. There are four main types of melanoma:

  • Superficial spreading melanoma is the most common type that accounts for approximately 70% of all cases. It usually begins as a pre-existing mole.
  • Nodular melanoma is the second most common type that accounts for approximately 15–30% of cases. It’s a more aggressive form that tends to develop faster.
  • Lentigo maligna melanoma accounts for approximately 4–10% of cases. It typically appears as large, flat skin lesions and has a lower risk of spreading.
  • Acral lentiginous melanoma accounts for approximately 2–8% of cases in fair-skinned individuals and up to 60% of cases in darker-skinned individuals. It’s usually present on the palms, on the feet or under the nail beds, and the lesions are very large in diameter.

Other rarer forms of melanoma include mucosal and ocular melanoma. Mucosal melanoma occurs in the mucosal tissue of body cavities or organs. Common sites include the head and neck and the gastrointestinal and genital regions. Ocular melanoma affects cells in the eyes and can occur in different parts of the eye.    

Early diagnosis and treatment lead to a high cure rate for melanoma in most cases. If you delay treatment, however, melanoma may spread to other parts of your body, making it difficult to treat successfully. Melanoma is responsible for the most deaths out of all skin cancers.