Skin Cancer 101: What is Melanoma?

Posted on September 23, 2022 in Skin Cancer

Written by Dr. Wild

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Melanoma is a type of skin cancer that occurs when pigment-producing skin cells (melanocytes) grow out of control. Melanoma can occur anywhere on the body, but it is most likely to develop in areas that have had exposure to the sun, such as the face, neck, chest, back, shoulders, and legs. For comprehensive info, download our free Skin Cancer eBook.

While melanoma is the least common type of skin cancer, accounting for only 2% of all skin cancer cases, it is also the most serious and dangerous.

In this article, we’ll discuss what melanoma is, how to recognize it, and steps you should take if you think you might have this type of skin cancer.

What is Melanoma?

melanoma on skin infographic

Human skin is made up of a handful of different types of cells. Each type serves a different role in the normal functioning of the skin.

Melanocytes are found in the deepest part of the top layer of skin, called the basal layer. They account for 5 to 10% of the cells in the basal layer.

Melanoma is a type of skin cancer caused by damage to the DNA of melanocyte cells in the skin.

Melanocytes produce melanin, a pigment in skin that is primarily responsible for skin color. When the cell’s DNA is damaged, it may cause it to mutate—leading to rapid, uncontrolled growth and the formation of malignant tumors.

Melanoma is considered highly curable when caught in its earliest stages, before the disease has spread. However, if not identified and treated quickly, melanoma may spread to other areas of the body, including distant organs.

If melanoma spreads (a condition called invasive melanoma) it may become difficult or impossible to cure. In these cases, melanoma can be fatal.

Here are some statistics from the American Cancer Society that highlight the seriousness of melanoma:

  • An estimated 207,390 new cases were diagnosed in the U.S. in 2021.
  • In 2021, an estimated 101,280 invasive melanomas were diagnosed.
  • An estimated 7,180 people in the U.S. die from melanoma in 2021.

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What Does Melanoma Look Like?

Melanoma lesions may form suddenly or may evolve from existing moles. While melanoma can take on many different forms, the general warning sign is a changing or atypical mole.

Melanoma frequently forms on areas of the skin that receive frequent exposure to UV light from the sun, including:

  • Back
  • Legs
  • Arms
  • Face

But melanoma may occur anywhere on the body, including palms, soles of the feet, and underneath fingernails. Rarely, melanoma can form in parts of the body other than the skin, such as the mouth, eyes, or intestines.

A melanoma lesion frequently looks like a mole in its earliest stages. Melanomas often appear as black or brown splotches, but may also be pink, white, blue, or purple. While melanoma often looks like a mole, it may also form as normal-looking skin that is sore, sensitive, or itchy.

Signs & Symptoms of Melanoma

Consult a doctor if you notice changes in your skin. These may include red flags such as:

  •  The sudden appearance of new moles or growths
  • Moles that change in size over time (exceeding 1/4 inch)
  • Asymmetrical moles
  • Moles with uneven borders
  • Moles that change in color
  • Moles that begin to itch, bleed, or become sore
Diagram showing where melanoma is most likely to develop

Melanoma vs. Normal Moles

normal mole vs atypical mole infographic

Moles are a normal part of skin for many people. Most people have between 10 and 50 on their body. Since many melanomas form from existing moles, it’s important to check your skin every few months and to know the signs of melanoma should they appear. To distinguish between them, here are some common characteristics of normal moles :

  •  Uniform color (often black, brown, or skin-colored)
  • Clearly defined edges with a distinct border between the surrounding skin
  • A round or oval shape
  • A diameter no larger than 1/4 inch, or roughly the size of a pencil eraser

Click here to view a printable version of the ABCDE chart.

Melanoma vs Other Skin Cancers

Melanoma is the most dangerous skin cancer, but it’s certainly not the only one. The two most common skin cancers include basal cell carcinoma and squamous cell carcinoma. Fortunately, these skin cancers aren’t life-threatening and are nearly always curable.

However, if left untreated, they can cause disfiguration and long-term nerve damage. For this reason, it’s important to take skin cancer – whether melanoma or another type – very seriously and consult your doctor if you suspect skin cancer.

To help you identify these skin cancers, basal and squamous cell carcinoma differ in appearance from melanoma. They also range in severity, depending on the skin tissue and the individual’s risk factors.

Basal cell carcinoma often looks like a flesh-colored bump or pink patch, and is commonly found on the head, neck and arms. Frequent sun exposure and indoor tanning are the strongest risk factors for getting this skin cancer. Those with fair skin may also be more prone to getting basal cell carcinoma.

Squamous cell carcinoma is another common skin cancer that often looks like a red bump or scaly patch. It’s frequently found on the face, neck, arms, chest and back. Once again, frequent sun exposure is the most significant risk factor.

Though these skin cancers aren’t as life-threatening as melanoma, it’s still essential to get early diagnosis to avoid their more serious consequences.

Melanoma Causes & Risk Factors

Long-term exposure to UV rays, or specific incidences of brief, intense exposure resulting in severe, blistering sunburns, are believed to be the most common cause of melanoma. Both sunlight and UV rays from tanning beds may cause damage. However, as with all cancers, melanoma is likely the result of both environmental and genetic factors.

The following characteristics may put you at greater risk of developing melanoma:

  • History of severe, blistering sunburn.
  • Fair skin. People with less melanin in their skin, those with light-colored eyes and blonde or red hair, and those with freckles, have less built-in protection from UV radiation and are at greater risk of developing melanoma.
  • Frequent sunburns in early childhood.
  • Family history of skin cancer, especially melanoma.
  • Having a large number of moles (more than 50) or atypical moles.
  • Weakened immune system, caused by medical conditions such as HIV/AIDS, or medical treatments such as chemotherapy.

How Melanoma is Diagnosed

Your doctor or dermatologist will first diagnose melanoma through a physical exam. He/she will check your skin from head to toe for typical signs of melanoma. This exam will take a thorough look at moles and skin tissues all over your body.

If any skin tissue seems suspicious, your doctor will perform a biopsy on it. The lab will then process it to find out if the tissue contains cancer cells.

If the results come by positive, your doctor will also analyze the melanoma to understand how far along the cancer is. By looking at the characteristics of the tissue (thickness, deepness, etc.) and whether it’s spread to other areas, he/she will identify the current stage of skin cancer.

Sometimes you may need to take additional exams, such as PET scans, CT scans, MRIs and blood tests so your doctor can fully understand the extent of melanoma. Generally speaking, melanoma is considered a lower risk if it’s localized, i.e. hasn’t spread to other areas of the body.

Melanoma Stages

Melanoma can be organized into several different stages, ranging from lowest to highest risk. In early stages (stages 0-2), the skin cancer hasn’t yet spread to other areas of the body, while in advanced stages (3-4), cancer cells may have reached lymph nodes or even organs.

In all stages of melanoma, you will require treatment to remove the affected skin tissue or undergo other appropriate therapies.

Overall, melanoma can be understood through these standardized stages of skin cancer:

  •  Stage 0: Melanoma is contained to the outermost layer of skin.
  • Stage I: Melanoma has penetrated the top layer of the skin and is smaller than 1 mm in depth.
  • Stage II: Melanoma is deeper than 1 mm, but still hasn’t spread to other areas. The risk for spreading may be high, especially if thicker than 4 mm or ulcerated.
  • Stage III: Melanoma has spread to the lymph nodes or a lymph vessel. The level of risk depends on how much it has progressed (i.e. how many nodes, how many cancer cells found in them, etc.).
  • Stage IV: Melanoma has spread to other lymph nodes or even organs, putting the patient at very high risk.

Your doctor will identify the stage of melanoma and create a plan to treat the cancer accordingly. Remember that melanoma detected in early stages is highly curable, with a 99% five-year survival rate.


Most people know that melanoma is a worrisome cancer. But there is good news. Eighty-four percent of melanoma patients present early, localized disease. That means that the cancer can still be removed, as it hasn’t yet spread to other areas of the body. Of that same group, 99% survive without recurrence of cancer at 5 years.

And yet, 9% of melanoma patients may experience regional spread of skin cancer to adjacent lymph nodes. In these cases, the cancer requires a more aggressive treatment that incorporates surgery, immunotherapy and radiation.

Fortunately, the success rate even with these more advanced melanoma tumors keeps improving, with most recent data showing a 66% 5-year disease-free survival rate.

Certainly, the best strategy with melanoma is aggressive screening for those at risk and excision of any suspicious skin lesions.

Screening Yourself for Melanoma

To protect yourself from a very curable but potentially deadly disease, doctors recommend regular self-checks at least every two months.

To help you know what to look for, consult the chart below. It only takes a few minutes every month to help protect against melanoma. In addition, you should get a full-body check once a year from a dermatologist or primary care provider.


ABCDE of moles graphic for spotting skin cancer

In Summary

Every year, 200,000+ new cases of melanoma are diagnosed in the United States. In about half of those cases, the disease will become invasive and spread from the site of the original tumor. An estimated 7,180 people will die this year of melanoma, which is a rate of nearly 20 deaths per day.

Bottom line: melanoma is a curable disease when caught early. While not all melanomas show symptoms before spreading, the vast majority of cases begin with an abnormal mole or growth on the skin. If detected during this stage, the cure rate is very high, so don’t hesitate to contact your doctor about an unusual mole or change in your skin.

To learn more about melanoma, including treatment options, contact a SERO physician by filling out the contact form on the sidebar, or by calling us at (704) 380-0730.