What Is Melanoma?

Melanoma is a skin cancer that arises from a skin cell called a melanocyte, which makes the pigment (melanin) that gives your skin its color. Melanoma can appear in different ways, most commonly as a new spot on the skin or as an already existing mole that changes in color, size, or shape. While considered the most dangerous type of skin cancer because of its ability to spread throughout the body rapidly, melanoma is generally very treatable if found early.

Melanoma

Types and Symptoms

Distinguishing between a cancerous and a normal mole can be challenging, even for healthcare providers. This is why a dermatologist should check out any new, changed, or out-of-place skin spot.

Potential signs and symptoms of melanoma include:

• Itching or other skin sensations like tenderness or pain
• Sore on the skin that does not heal
• Bleeding or oozing from a mole
• Change in the surface of a mole, like a lump or bump
• Spread of pigment from the border of a mole into the surrounding skin
• Redness or swelling surrounding a mole

This list is not all-inclusive, but is limited in common symptoms. Each of the four main subtypes of melanoma can present with unique characteristics. Moles with a diameter the same size or larger than a pencil eraser should be evaluated.

Superficial Spreading

This is the most common subtype of melanoma in people with fair skin. It usually begins as a brown or black spot that is asymmetric, has irregular borders, and exhibits changes in color.

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Nodular

After superficial spreading melanoma, nodular melanoma is the next most common type of melanoma in fair-skinned individuals. Instead of growing outward, this melanoma grows vertically (deep into the skin).

Nodular melanoma usually begins as a dark or lightly colored (pink hue) raised spot.

Lentigo Maligna

This subtype of melanoma is most common in chronically sun-damaged areas of skin in older adults. Lentigo maligna typically starts as an irregular-shaped tan or brown spot that grows slowly over the years to form a larger spot that becomes asymmetric and/or develops color changes or raised areas.

Acral Lentiginous

This subtype accounts for less than 5% of all melanomas. However, it is the most common type among dark-skin individuals.

Acral lentiginous melanoma usually appears on the palms of the hands or soles of the feet as an irregularly-shaped growth or an elevated, thickened patch that is changing in color or size. It may also appear underneath a fingernail or toenail as a brown or black streak or band.

Complications

If melanoma grows large and spreads to other regions of the body, it may cause symptoms related to that spread. For example, a melanoma that has spread to the liver may cause jaundice, a yellowish discoloration of the skin.

Cancers that have spread may also cause systemic symptoms such as fatigue, unintentional weight loss, and weakness.

Causes

Melanoma develops when DNA changes occur within melanocytes. These DNA changes cause once normal, healthy skin cells to turn into cancer cells that grow uncontrollably.

Ultraviolet (UV) radiation from natural or artificial sources, including tanning beds and sun lamps, is a major cause of melanoma because UV rays can directly damage the DNA within skin cells. Besides UV exposure, other risk factors that increase your risk of developing melanoma include:

• Having fair skin, natural red or blond hair, and/or blue or green eye color
• A family or personal history of melanoma
• Having a large number of moles (more than 50)
• Older age
• Being male
• Having many freckles or developing freckles easily
• A history of sunburns
• Having a disease or taking a medication that weakens your immune system

Bear in mind that people with dark skin can get melanoma, and due to similarities in color between the skin and the mole, these cases can be more difficult to diagnose. In addition, people without any risk factors or who have had very little sun exposure or wear sunscreen can get melanoma.

Diagnosis

Diagnosing skin cancer typically begins with a medical history and skin exam by a dermatologist. Your healthcare provider will access your risk factors for skin cancer, such as your history of sunburns and your family history of melanoma.

In assessing for potential melanoma, they will also consider other possible conditions. For example, sometimes acral lentiginous can mimic benign (noncancerous) conditions, like warts, ingrown toenails, calluses, or athlete's foot.

Skin Examination

During the skin exam, your healthcare provider will carefully examine your skin for suspicious marks or spots, noting their size, shape, color, and texture. They may use a tool called a dermatoscope, which is an instrument that contains a light and magnifying lens to better visualize skin spots.

ABCDE Rule

To help sort out normal moles from melanoma, a mnemonic—the ABCDE rule of melanoma—is often utilized by dermatologists during skin exams. People can also use this as a guide to seeing a dermatologist as soon as possible.

The ABCDE rule spotlights the characteristics by which you assess a suspicious mole:

• Asymmetry: In the case of skin cancer, spots will not look the same on both sides.
• Border: A mole or spot with blurry and/or jagged edges would be considered concerning.
• Color: Melanomas tend to be "more colorful" than regular moles. Different colors or shades in the same mole are also of concern.
• Diameter: Melanomas tend to be larger than normal moles (but certainly not always).
• Evolution: This refers to any change in a mole (e.g., texture, degree of elevation, size, color) 

Another potential warning sign of melanoma is a mole that stands out from other moles due to its different appearance—even if it does not fulfill the above ABCDE criteria. This is referred to as the "ugly duckling" sign.

Skin Biopsy

A skin biopsy will be performed if there is any suspicion of melanoma or any other type of skin cancer or abnormality. With a skin biopsy, a dermatologist removes a sample of the suspicious "spot," which can then be examined under a microscope for cancer cells by a type of healthcare provider called a dermatopathologist.

Sometimes, to confirm the diagnosis of melanoma or to further evaluate the genetic pattern of the melanoma cells (which can affect melanoma treatment and prognosis), a dermatopathologist will perform additional tests on the biopsy sample in the lab.

Imaging Tests

If the biopsy results show the presence of melanoma, imaging tests, such as a chest X-ray or computed tomography (CT) scan may be performed to determine if and how far the disease has spread.

Staging

After you’re diagnosed with melanoma, your dermatologist will then stage cancer. Staging tells you how deeply the melanoma has grown into the skin and how far it has spread. Melanoma is grouped into the following stages:

• Melanoma In Situ (Stage 0): Cancer cells are only in the top layer of the skin
• Stage 1: An early diagnosis of cancer cells are only in the skin cells and have not spread to the lymphatic system or anywhere else in the body
• Stage 2: Cancer cells are only in the skin and have not spread
• Stage 3: Cancer cells have spread to the lymph nodes
• Metastatic Melanoma (Stage 4): Melanoma cells have spread (metastasized) beyond the original site of the skin and lymph nodes to a distant location in the body, such as the brain, liver, or lungs

Your healthcare provider will use the stage to determine your cancer treatment.

Treatment

There are currently five methods of treating melanoma—surgery, immunotherapy, targeted therapy, chemotherapy, or radiation therapy. Treatment depends largely on how deeply the melanoma has grown, whether cancer has spread, and your overall health.

Surgery

All melanomas (except those known to have metastasized already) will be surgically removed along with a wide margin of normal skin. The procedure might also include a biopsy of a nearby lymph node to evaluate whether the melanoma has spread.

Advanced Melanoma

Two types of therapies may be recommended if the disease is more advanced. Immunotherapies are drugs that stimulate a person's immune system to attack cancer. Targeted therapies are drugs that attack melanoma cells containing specific gene mutations.

Chemotherapy, which are drugs that kill rapidly growing cells like cancer cells, is generally considered a second-line treatment for melanoma. Radiation therapy is an uncommon treatment for melanoma and is only used in select cases.

Prevention

While you cannot control all of your risk factors for developing melanoma (e.g., having fair skin or your family history), you can protect yourself from sun exposure to UV rays. Strategies to reduce your overall UV exposure include:

• Avoiding the sun during midday (especially from 10 a.m. to 2 p.m.)
• Using protective clothing to cover your skin
• Applying sunscreen
• Seeking shade to reduce sun exposure
• Wearing sunglasses and a hat or using an umbrella when outside in the sun
• Avoiding tanning beds and sunlamps

Performing Skin Self-Exams

In addition to minimizing UV exposure, regular skin self-exams are important for detecting a new or abnormal growth before it can turn into melanoma or another type of skin cancer.

When doing a skin self-examination, you need to look at all areas of your body, including your elbows, underarms, buttocks, back, back of your neck, scalp, palms, soles of your feet, and spaces between your toes, and underneath your nails. It helps to have a mirror to view difficult-to-see areas.

Look for any changes to color, shape, and size of any freckle, mole, blemish, reddened, itchy, or bleeding areas. If you find anything concerning, make an appointment to see your dermatologist.

Summary

Melanoma is a type of skin cancer that spreads quickly. Various types can affect people with all skin colors, specifically those with lighter skin or many moles and freckles. There are different treatments for melanoma, depending on the staging determined by your healthcare provider.

A Word From Verywell

A major message here is that if you find a new or changing mole, patch, or spot on your skin, don't ignore it. Get it looked at as soon as possible by a dermatologist. Skin cancers can be treated if found early, but they can be life-threatening if left to advance.

Lastly, as with all types of cancers, prevention is key. This includes reducing your exposure to direct sunlight and other forms of UV radiation and covering up with sunscreen and protective clothing as much as possible.