What Is Melanoma?
Melanoma is a type of skin cancer that occurs when pigment-producing cells—known as melanocytes—mutate and become cancerous. Melanoma is the most serious form of skin cancer and is one of the most common cancers among both men and women. Even though invasive melanoma accounts for only about 1% of all skin cancers, it is responsible for the majority of deaths from skin cancer. Melanoma is dangerous because it is more likely to spread, or metastasize, than other skin cancers, such as basal cell carcinoma and squamous cell carcinoma.
Most pigment cells (melanocytes) are found in the skin; therefore, the majority of melanomas are found on the surface of the skin, such as on the back, neck, or legs. But melanoma can also occur in the nail bed (acral lentiginous melanoma), in the eyes (ocular melanoma), and on internal mucosal surfaces (mucosal melanoma), such as the lining of the sinuses, mouth, anal canal, or vagina.
Melanoma can develop anywhere melanocytes are found, but certain areas are more prone than others. In men, it is most likely to affect the back and the head/neck area. In women, the legs are the most common site. Other common sites are the neck and face. Children can also develop melanoma.
In 2024, an estimated 200,340 cases of melanoma will be diagnosed in the United States. Of those, 99,700 cases will be in situ (noninvasive), confined to the top layer of skin (the epidermis), and 100,640 cases will be invasive, penetrating the epidermis into the skin’s second layer (the dermis). Of the invasive cases, 59,170 will be men and 41,470 will be women.
The number of new cases of melanoma has steadily increased for the last 30 years. Death rates were increasing through 2016, then began to decrease, likely due to improvement in overall survival as a result of new treatments.