What is Melanoma?

What is Melanoma?

Melanoma is the most invasive form of skin cancer. It develops in melanocytes—the skin cells that produce the dark pigment (melanin) that gives your skin its color.

Melanoma typically develops in an existing mole or appears as a new mole on the skin's surface. Melanomas can appear anywhere on the body, including as “hidden melanomas” in the eye, mouth, scalp, or under a nail.

Skin cancer is one of the most common forms of cancer in the United States, but melanoma accounts for only 1% of skin cancers. Melanoma has 99% five-year survival rate if detected and treated early.

Types of Melanoma


Melanoma can also be referred to as malignant melanoma or cutaneous melanoma. Invasive melanoma is any melanoma that is defined as stage I-IV.

In general, there are four main types of melanoma:

  • Superficial spreading melanoma. This is the most common type of melanoma. It develops on the top layer of the skin in a new mole or in an existing mole, causing the mole to change shape. It can penetrate deeper into the skin over time.
  • Nodular melanoma is an aggressive form of melanoma. It can spread faster than other types, and usually presents as a node or a bump on the legs, arms, torso, or scalp.
  • Lentigo melanoma and lentigo maligna melanoma. Lentigo melanoma is an early stage of melanoma, when the skin cancer is confined to the original tissue. Lentigo maligna melanoma is the advanced stage, when the lentigo melanoma has spread. Both occur in sun-damaged skin, usually on the nose, cheek, and other parts of the face and neck.
  • Acral lentiginous melanoma. This form of melanoma can develop in the extremities of the body—the soles of the feet, palms of the hands, and under the fingernails or toenails.

Other forms of melanoma can include:

  • Ocular melanoma. This is a rare form of cancer that affects the eye.
  • Amelanotic melanoma. An invasive form of cancer, amelanotic melanoma doesn’t first appear as dark spots. Instead, it appears as skin-colored, reddish, or pink spots with brown or gray edges.
  • Subungual melanoma is a rare and aggressive cancer that first appears as a black or brown streak under the toenails or fingernails.

Stages of Melanoma


Once diagnosed, melanomas are classified into stages based on how advanced and widespread the cancer is. The thickness of the tumor also plays a factor in staging. Identifying the stage of the melanoma is important, as it will influence the course of treatment.

Melanomas can be grouped into the following stages:

  • Stage 0 melanoma (melanoma in situ). Cancerous cells are detected on the top layer of the skin (epidermis), and have not spread beyond the site.
  • Stage 1 melanoma. The tumor’s thickness is 1mm, and has not spread beneath skin or beyond the original site. This stage is usually treatable with surgery.
  • Stage 2 melanoma. The tumor’s thickness is more than 1mm and has penetrated beneath the skin, but has not spread to other sites. This stage may be treated with a wide excision surgery, removing the cancer and a margin of healthy surrounding tissue.
  • Stage 3 melanoma. The cancer has spread from the primary site to nearby skin or lymph nodes.
  • Stage 4 melanoma. The cancer has spread to the lymph nodes or the internal organs.

Symptoms & Signs of Melanoma


Melanomas are highly curable if detected early. It’s important to recognize melanoma symptoms so you can seek treatment as soon as possible.

The American Academy of Dermatology provides a helpful mnemonic guide to help spot cancerous growths on the skin.

Here are the “ABCDE” warning signs of melanoma:

  • A for Asymmetry. The spot has one side that doesn’t match the other.
  • B for Border. The spot’s border is undefined or irregular.
  • C for Color. The spot varies in color with shades of black, gray or brown, or sections of red, pink, blue or white.
  • D for Diameter. The spot is larger than 6mm—about the size of a pencil eraser.
  • E for Evolving. The spot keeps changing in size, color, or shape.

Causes of Melanoma


In cases of melanoma, DNA in the skin cells becomes damaged and mutates, growing and spreading to overtake healthy surrounding tissue. There is no exact known cause as to why this DNA mutation occurs.

However, there are risk factors that can be directly linked to increasing the likelihood of developing melanoma, including:

  • UV light exposure. Too much time in the sun or in a tanning bed can damage skin cells, leading to the potential development of melanoma.
  • Sunburn. A sunburn can lead to an increased risk of developing skin cancer.
  • Fair skin. Having a light-skinned complexion—blonde or red hair and light-colored eyes—means you may freckle and sunburn easily, putting you at higher risk of developing melanoma.
  • Living at a higher elevation or near the equator. If you live in a part of the world that receives more direct sunlight, you may be more frequently exposed to intense UV radiation.
  • Prone to many or unusually-shaped moles. You could be at greater risk for melanoma if you have more than 50 moles or have many atypically shaped moles.
  • A weakened immune system can raise your risk of melanoma, whether you have an autoimmune disease or are taking medication that suppresses your immune system.
  • Family history. Having a close family member diagnosed with melanoma can increase your risk of developing the condition.

Melanoma Prevention


Anyone can develop melanoma, but the best way to lower your risk factor is to protect yourself from the sun:

  • Avoid direct sun exposure, especially between 10 a.m. and 4 p.m.
  • Apply sunscreen with an SPF of 30 or higher when outside for prolonged periods. Take care to reapply after swimming or sweating.
  • Use a daily facial moisturizer with 30 SPF or higher
  • Use a lip balm with sunscreen
  • Protective clothing. Wear long-sleeved shirts, broad-brimmed hats, and long pants to minimize sun exposure.
  • Avoid tanning beds
  • Schedule regular mole checks. A dermatologist can help determine if a mole or a skin discoloration is precancerous or a melanoma.
Get Care

Trust NewYork-Presbyterian for Melanoma Cancer Care

NewYork-Presbyterian houses top-notch cancer care experts specializing in diagnosing and treating melanoma and all types of cancer, such as breast, colon, lung, brain, prostate, kidney, blood, and bone cancer. Our preventive melanoma methods include MoleMap photography, which tracks atypical moles over time to help people with higher risks for developing melanomas.

Melanoma is highly treatable if detected early. If you have a suspicious mole or skin discoloration, reach out to NewYork-Presbyterian for a skin screening appointment today.