Amelanotic melanoma may have an irregular border, uneven pigmentation, and a raised surface.
A Guide to Amelanotic Melanoma and How It Differs from Other Skin Cancers
Keep reading to learn about what AM looks like, the stages of this cancer, and available treatments.
AM is a type of skin cancer in which the cancerous cells have little or no melanin. Melanin is the pigment that gives skin its color.
Because the tumors that develop in AM stand out less from the skin than other types of skin cancer, they can be more difficult to detect. As a result, doctors often diagnose AM at an advanced stage, which makes the outlook more challenging than for pigmented skin cancers.
Signs of amelanotic melanoma
Signs of melanotic melanoma
Symptoms of amelanotic melanoma can include bleeding, oozing, or crusting.
Signs of amelanotic melanoma
Areas of amelanotic melanoma may appear pink or light brown.
Due to the lack of pigment, an AM lesion can be hard to spot. However, the Skin Cancer Foundation says that AM can appear pink, red, or purple. It may also be clear or blend in with your natural skin color.
The lack of melanin also means AM does not necessarily follow the same ABCDEs of melanoma criteria that doctors recommend to identify other melanomas. However, certain symptoms can also occur with AM, including:
- irregular borders
- size changes
- asymmetrical shapes
To screen for AM, DermNet in New Zealand recommends adding the three Rs as guidelines to identify areas that have:
- raised tissue
- recent changes
One key symptom of AM is a patch of atypical skin that appears suddenly. Although AMs lack the pigment that makes other melanomas dark, they can still have a distinctive look with the following features:
- color that matches your skin tone
- pigment that appears pink or light red
- edges that can be gray or light brown
AM can also produce symptoms similar to those of other types of melanoma, according to the Skin Cancer Foundation. These can include:
- sore or tender skin
- areas of bleeding
- crustiness or oozing
- changes in size, shape, or color
- new raised area on the skin
Where can amelanotic melanoma occur?
AM can appear anywhere on the body. Ultraviolet (UV) exposure is a risk factor, so AMs often appear on areas of skin that receive more sun exposure.
How fast does amelanotic melanoma spread?
Compared with other skin cancers, melanoma overall is more likely to spread, according to the American Cancer Society.
For AM specifically, a 2014 study suggested that AM tumors may grow faster than those associated with other types of melanoma.
However, it is important to note that every case of AM is different and progresses at its own rate.
When making a cancer diagnosis, doctors use staging to classify the size and spread of the cancer.
Medical practitioners use the TNM system from the American Joint Committee on Cancer to evaluate melanoma staging:
- tumor, describing the size and placement of the primary tumor
- lymph nodes, determining if the cancer spread to nearby lymph nodes
- metastasis, determining if the cancer spread
Additionally, doctors classify melanoma from stages 0–4:
- Stage 0: In this stage, the melanoma reaches the top layer of skin, known as the epidermis.
- Stage 1: Stage 1 indicates that the melanoma is still localized, meaning it is only present in one section. Stage 1 melanomas penetrate the second layer of skin, known as the dermis. Melanomas at this stage are between 1–2 millimeters (mm) thick.
- Stage 2: Cancer at this stage is thicker than 2 mm. However, there is no evidence that cancer has spread to the lymph nodes or distant sites.
- Stage 3: At stage 3, cancer has spread to nearby lymph nodes. In certain stage 3 substages, the AM lesion may have ulcerated, which means it turns into a sore that will not heal on its own.
- Stage 4: Metastasis, the spread of cancer to distant sites, is the key sign of stage 4 cancer. Cancer at this stage may also spread to other body organs.
Your doctor will discuss your AM diagnosis with you in detail, including an explanation of staging. Based on staging information, your doctor can discuss available treatment options.
According to the Skin Cancer Foundation, the primary cause of skin damage is exposure to UV light, such as through natural exposure to the sun’s rays or use of UV tanning beds.
Research from 2019 showed that AM can occur more frequently in people more than 50 years old or with:
- a previous diagnosis of AM
- absences of moles on the back
- a large amount of freckles
- red hair
- less skin pigment
Doctors begin the AM diagnosis process by examining the impacted area both visually and through a dermatoscope. They may also ask you questions about your family history, sunscreen usage, and amount of average sun exposure.
To diagnose amelanotic melanoma, your medical professional will need to perform an excision biopsy of the affected area. Surgeons remove the tumor and a margin of skin around it, then send the tissue to a laboratory for analysis.
If the results indicate melanoma, you will likely undergo another excision procedure to remove a wider portion of tissue. The margin of the excision will depend on factors including the thickness of the tumor and its location.
Depending on the size of your tumor, your doctor may also recommend a sentinel lymph node biopsy. This procedure removes a sample of nearby lymph node tissue to determine if the melanoma spread.
Doctors follow the same treatment approach for AM and pigmented melanoma. AM requires the removal of the lesion.
The surgeon will also remove a portion of healthy skin around the melanoma as a safety margin. The width of the safety margin increases depending on how deep the melanoma goes.
Smaller lesion removal is an outpatient procedure, which means it does not require an overnight hospital stay. However, larger lesions may require more postsurgery monitoring and a skin flap or skin graft. These procedures attach healthy skin to the affected area from another portion of the body.
Depending on the stage of your AM, doctors may recommend additional treatments after surgical removal of the tumor, including:
- targeted drugs
Your doctor will discuss all of your treatment options, including potential benefits and risks, so you can work together to find the treatment plan that is right for you.
A 2014 study showed that the 5-year survival rate for AM is 88%.
Survival rate refers to the number of people who are still alive for a specific length of time after a particular diagnosis.
For example: A 5-year survival rate of 50% of people means that half of the people are still alive 5 years after their diagnosis.
It is important to remember that these figures are estimates and are based on previous medical studies. Talk with your doctor about the outlook for your specific condition.
In its early stages, AM usually responds well to treatment. Late stage AM is more aggressive and harder to treat if cancer spreads to the internal organs.
The absence of pigment in AM makes it difficult to diagnose. This often leads to treatment delay, which can negatively affect treatment outcomes. Accurate and early detection paired with treatment can improve the outlook and increase survival rates of this disease.
These are some other questions people often ask about amelanotic melanoma. Raechele Gathers, M.D., has reviewed the answers.
Is amelanotic melanoma serious?
AM is a serious form of skin cancer. Since the affected area contains little or no pigment, it is difficult to detect in its early stages. However, AM has a relatively high 5-year survival rate, and the outlook improves with early detection.
Does amelanotic melanoma appear suddenly?
One key symptom of AM is a lesion that may appear suddenly. This lesion may feel sore and crusty. The edges may contain some pigment and the center may match your skin tone or appear red, pale pink, or tan.
AM is a serious form of skin cancer involving a lack of pigment. AM lesions can change in shape and size rapidly and often have an irregular border. Risk factors include certain inheritable characteristics and UV exposure.
Doctors treat AM through surgical removal, but advanced stages may require additional treatment like skin grafts, immunotherapy, and targeted drugs. Earlier stages have a better outlook than advanced stages.
Contact your dermatologist about skin lesions or areas that appear suddenly, have unusual changes, or cause you concern.