Melanoma: Definition, Causes, Risk Factors, Symptoms, Types, Diagnosis, Treatment and Prevention

It is a serious type of skin cancer. It starts in cells that produce melanin (melanocytes), which is the pigment responsible for skin color.

Melanoma can appear in the eyes and can also develop in internal organs, such as the intestines, however this happens rarely.

Melanoma usually appears as:

  • An irregular brown, black, or red spot.
  • A mole that begins to change color, size, or shape.

Melanoma occurs most often in the trunk area in light-skinned men and on the lower legs in light-skinned women.

In individuals with dark skin, melanoma frequently occurs on the palms of the hands, the soles of the feet, and the skin under the nails.

When diagnosed early, melanoma is usually curable.


The exact cause is unclear, but scientists believe that when something goes wrong with melanocytes , which are the cells that make melanin and give skin its color, cancer occurs.

Normal skin cells always develop in an orderly and controlled way, and older cells are pushed to the surface of the skin when new cells form.

Old cells die and gradually shed.

In melanoma, there is some deterioration in the DNA of the cells that leads to uncontrollable growth and division of new cells that results in the formation of a mass or tumor of cancer cells.

Risk factors for melanoma

  • People with fair skin have less melanin in their skin, which means that they receive less protection from UV rays. Therefore, people with light-colored eyes, blonde or red hair, and who burn easily in the sun have a higher risk of developing melanoma compared to people with darker complexions.
  • People with excessive exposure to UV radiation are at increased risk of developing skin cancer, including melanoma.
  • Having a previous history of sunburn increases your risk of melanoma.
  • People who live near the equator or higher are at higher risk of developing melanoma.
  • People who have many moles (over 50) are at a higher risk for melanoma. If the mole is not like an ordinary mole and has an unusual appearance, such as dysplastic nevi, which are larger than normal moles with a combination of colors and uneven edges, they are more likely to have melanoma.
  • People who have weak immune systems are at a higher risk of developing skin cancer.

Having a family history of melanoma increases your risk of developing it. Some risk factors are beyond your control, such as complexion or family history. However, some risk factors, such as sun exposure, are factors that you can control.

Dark or dark brown skin is not a guarantee against melanoma.

African Americans, Latinos, and Asians are at lower risk for the most common types of melanoma related to the sun.

Melanoma Signs and Symptoms

Like most cancers, the best treatment for melanoma is when it is diagnosed early.

Recognizing the warning signs of melanoma can help you know when to seek treatment.

Because the symptoms of melanoma may resemble other medical conditions or problems, it is important to see your doctor immediately for evaluation.

Each individual may experience different skin findings or symptoms.

Signs and symptoms can include:

  • Change in the size, shape, color, or elevation of a mole.
  • Oozing or bleeding from a mole
  • A mole that looks different from other moles or feels itchy, hard, bumpy, swollen, or tender to the touch.

Melanoma can spread to other parts of the body through the lymphatic system or through the bloodstream. Melanoma tumors are often brown or black in color. However, they can also be flesh-colored, bluish, or pink.

Melanoma can also appear on the body as a “new” pigmented lesion, not arising from a pre-existing mole.

Most melanomas start on the skin and are called cutaneous melanoma.

In rare cases, melanomas can form in parts of the body that are not covered by the skin, such as the eyes, mouth, genital region, and brain.

To find melanoma early, when it is most treatable, it is important to examine the skin regularly.

Become familiar with moles and other skin lesions, so that you can identify any changes.

However, the vast majority of melanomas do not come from a pre-existing mole (common, congenital, or dysplastic types). Therefore, we do not recommend mass removal of stable, benign-looking moles.

The ABCDE chart showing the signs of skin cancer helps you recognize changes in moles.

The warning signs of ABCDE are:

  1. A: Asymmetry. When half of the mole does not match the other half.
  2. B: Edge. When the edge (edges) of the mole is uneven or irregular.
  3. C: Color. When the color of the mole varies (multiple shades of brown, black, white, red or blue).
  4. D: Diameter. If the diameter of the mole is larger than a pencil eraser (usually 5 to 6 mm in diameter).
  5. E: Evolution. A mole or skin lesion that looks different from the rest or changes in size, shape, or color.

Melanomas vary greatly in appearance.

Melanomas may manifest all of the features, while others may reveal only few or none of these warning signs.

The “ugly duckling” sign can also be a helpful way to detect melanoma at an earlier stage.

This simply involves looking at the skin for a lesion that does not match the rest.


There are several types of melanoma, and the treatment and outlook for each are different:

  • Cutaneous melanoma.
  • Melanoma of the mucosa.
  • Ocular melanoma.

Diagnosis of melanoma

To diagnose melanoma, a careful inspection of the skin and a biopsy of suspicious skin lesions are performed.

Most of the time, the lesion is pigmented (tan, brown, black, or bluish in color) but can sometimes be “amelanotic” (flesh-colored, pink, or red in coloration).

The physical exam includes a dermoscopic evaluation, the use of a magnifying device to look closely at the moles. The lesion of interest is examined, as well as moles and skin on the rest of the body.

It is important to specifically analyze the size, shape, color, texture, and presence of bleeding or scales.

Research should also be done on:

  • Complete medical history, including family history.
  • Time, changes, bleeding, pain, itching from lesions or moles.
  • If melanoma is suspected, your doctor will most likely order a biopsy to confirm the diagnosis.

The most commonly used tests for the diagnosis of melanoma are:

Skin exam for melanoma

The dermatologist checks the skin for moles or other pigmented lesions that look abnormal in color, size, shape, or texture.


A biopsy procedure is performed under local anesthesia to remove as much of the suspicious mole or lesion as possible.

The pathologist then looks at the tissue under a microscope to check for cancer cells.

Because melanoma can be difficult to diagnose, it is important to have an evaluation by a dermatopathologist.

The types of biopsies used to diagnose melanoma include:

  • Skin biopsy : This involves removing a sample of skin to examine it under a microscope.
  • Excisional biopsy: Also called a wide local excision, an excisional biopsy involves the surgical removal of a tumor and some normal tissue around it. The amount of normal tissue that is taken (also called the clinical margin) depends on the thickness of the tumor.
  • Needle biopsy: This involves taking a deeper sample of the skin with a biopsy instrument that removes a short cylinder of tissue.
  • Shave biopsy: This type of biopsy involves taking a sample from the upper layers of the skin. Shave biopsies are also done under local anesthesia.
  • Fine needle aspiration biopsy: Involves the removal of tissue, fluid, or very small pieces of a tumor with a fine needle.

Additionally, the doctor may request advanced studies as part of his diagnosis such as:

Genotyping: Much of current cancer therapy is directed toward specific gene mutations in cancer cells and signaling pathways. This requires the rapid and accurate identification of genetic abnormalities that can predict the patient’s response to a specific drug.

This is a highly sensitive clinical test to identify several of the most common genetic changes that cause melanoma.

In Situ Fluorescent Hybridization: This diagnostic detects genetic mutations in order to aid in the diagnosis of melanoma and differentiate benign from malignant tumors.

A four-probe fluorescent in situ hybridization assay can improve the early classification of melanomas and has been shown to aid in the diagnosis of melanoma cases that are difficult to diagnose.

Melanoma staging

Tests may also be done to find out if melanoma cancer cells have spread to other parts of the body.

This is called staging, and it is necessary to determine the best treatment plan and its management.

The stages of melanoma are:

  • Stage O.
  • Etapa I (1).
  • Stage II (2).
  • Stage III (3).
  • Stage IV (4).


Melanoma treatment often includes these five types of standard treatment options:

  • Surgery is performed to remove early stage melanomas where the melanoma is removed along with a margin of skin surrounding the lesion, the underlying layer of tissue.
  • If the melanoma is very thin, it can be completely removed during the biopsy and does not require further treatment.

When melanomas are in an advanced stage, treatment consists of:

  • Surgery: This is done to remove the lymph nodes that have been affected by melanoma.
  • Chemotherapy: Drugs or chemicals are used to kill cancer cells. It can be given as a pill or through an IV.
  • Radiation therapy: involves the use of high-powered energy beams that are directed at specific points in the body to kill cancer cells. A common side effect of radiation therapy is fatigue; however, energy levels often return after treatment is complete.
  • Biological therapy : is aimed at increasing the immune system, which helps the body fight cancer. Biological treatment includes interleukin-2 and interferon. Ipilimumab (Yervoy) is generally used to treat advanced melanomas that have already metastasized.
  • Targeted therapy: involves the use of drugs that target specific abnormalities of cancer cells. Emurafenib (Zelboraf) is used to treat advanced melanoma that does not respond to surgery.

Prevention of melanomas

Steps can be taken to reduce your risk of developing melanoma.

Protecting yourself from the sun and getting regular skin checks.

If anything unusual is noticed about moles or any other skin change, a doctor should be consulted for a proper diagnosis.

Some risk factors for melanoma are out of control. However, some risk factors can be reduced.

The following recommendations should be considered to help reduce your risk of skin cancer:

  • Clothing: Wear protective clothing, including a long-sleeved shirt, pants, a wide-brimmed hat, and sunglasses, when possible.
  • Sunlight: seek shade when necessary, especially when the sun’s rays are most intense, from 10 am to 4 pm
  • Sunscreen: Regularly use a broad-spectrum sunscreen with an SPF (sun protection factor) of 30 or higher on all exposed skin, even on cloudy days. Reapply sunscreen every 2 hours and after swimming or sweating.
  • Children: protect children from the sun using shade, protective clothing and sunscreen.
  • Caution around water, snow, and sand: Take extra care when around water, snow, and sand, as these elements can reflect the sun’s rays and increase the chances of sunburn.
  • Avoid tanning beds – Ultraviolet (UV) light from tanning beds causes skin cancer, including melanoma and accelerated photoaging, wrinkles, and sagging skin.
  • Annual self-assessments: check the skin annually, use the birthday date as a reminder. Look at the skin carefully and if you notice any lesion that changes, grows or bleeds on the skin, consult your doctor.
  • Vitamin D: consume vitamin D from the adoption of a healthy diet with vitamin supplements.