What is Atypical Mole?
Atypical moles, also known as dysplastic nevi, are certain growths on the skin that represent an abnormality in the skin’s pigment cells called melanocytes. They are also referred to by different names such as Clark nevi or B-K moles. However, technically, the term “dysplastic nevus” applies to a specific condition that only a small number of atypical moles meet the criteria for. Often, they may look like melanoma, a type of skin cancer, because they share similar characteristics.
An atypical mole’s diagnosis is usually based on the presence of three or more certain traits, including being larger than 5 mm, having unclear borders, irregular edges, and variable colors within the mole itself. Doctors often decide to biopsy, or remove a small piece of these moles to check for melanoma, as it can be challenging to ensure it’s benign just by looking at it. Although individuals with many atypical moles have a higher chance of developing melanoma, the chances of an individual atypical mole becoming malignant, or cancerous, is pretty low.
What Causes Atypical Mole?
The exact cause of atypical moles isn’t fully understood yet. What we do know is that it has a lot to do with a mix of your genes and environment.
People who have certain traits are more likely to get atypical moles. This includes having fair skin, blonde hair, light-colored eyes, being prone to freckles, and having skin that’s sensitive to the sun. Research has shown that people who are exposed to a lot of UV sunlight are more likely to develop atypical moles.
Genes are also thought to play a part. Studies across the entire genome have found a link between the amount of certain types of moles and genes known as IRF4, PLA2G6, and MTAP.
One theory is that atypical moles are a step in the process of developing melanoma, a type of skin cancer. This theory suggests that regular moles become atypical moles, which then can develop into melanoma. Some dermatologists still hold this view. However, the evidence isn’t very strong for this theory. For instance, most people who have a family history of melanoma express a gene called CDKN2A, but this gene isn’t usually seen in people with atypical moles. Plus, since about 75% of melanomas appear without any previous history, it raises questions about the validity of this theory.
Risk Factors and Frequency for Atypical Mole
Atypical moles, also known as unusual spots on the skin, are spread worldwide and occur marginally more in men than women. They appear in 2% to 18% of people across the globe. Europeans and fair-skinned individuals are more prone, with a prevalence of 7% to 24%. Nevertheless, a few exceptions exist, such as in Japan, where despite the lighter skin complexion, the occurrence of atypical moles is minimal. The incidence is also infrequent in children.
In the United States, less than 1% of the population is at risk of developing melanoma in their lifetime. However, people who have atypical moles face a much higher risk, more than 10%. The chances of common moles turning into melanoma are low, approximately 1 in 30,000 for men and 1 in 40,000 for women. Regular moles rarely turn into unusual moles, with three-quarters of atypical moles emerging from nowhere and not replacing an existing mole at their site.
People with a condition called Familial Atypical Multiple-Mole Melanoma Syndrome (FAMMM) are at an especially high danger, as they have nearly a 100% chance that an odd mole will transform into a melanoma in situ during their lifetime.
Signs and Symptoms of Atypical Mole
Atypical moles are abnormal-looking moles that can appear in different shapes. They can be flat, slightly raised, or look similar to pigmented growths on the skin. These moles are mostly found in areas exposed to the sun, but they are most common on the trunk in men and calves in women. Doctors identify these moles during a physical exam by using the ‘ABCDE’ guideline:
- Asymmetry
- Irregular borders
- Color variation
- Diameter larger than 6mm
- Evolution or changes in the mole
Atypical moles usually show up during childhood or early teen years. They are uncommon in people over 60 and, when they show, it could potentially be an early sign of melanoma. There are five different types of atypical moles:
- ‘Fried-egg’ type: Has a raised, dark brown middle surrounded by a slightly elevated, lighter brown area.
- Lentiginous type: Completely flat and brown or dark brown in color.
- Seborrheic keratosis-like type: Dark brown with a rough surface resembling a type of skin growth known as seborrheic keratosis.
- Target type: Has a central zone with varying pigmentation.
- Erythematous type: Usually pink with very little pigmentation.
People can have different numbers of atypical moles. If someone has more than 100 of these moles, a condition called dysplastic nevus syndrome might be considered. This can be random or hereditary, and it’s diagnosed if the person has at least 100 atypical moles larger than 8mm.
Testing for Atypical Mole
If a doctor suspects you may have unusual skin moles called “atypical moles,” they will usually need to completely remove the mole to properly examine it. The removal process, known as an excision biopsy, gives a full picture of the mole’s features under the microscope. A less invasive method, the incision biopsy, is not ideal because it could miss areas of skin cancer, known as melanoma, within the mole.
Removing atypical moles doesn’t completely prevent skin cancer. If you have a large number of these moles, it’s important to check your skin regularly as you could still develop melanoma.
Dermoscopy, a skin examination method, can be used to study areas of skin that look suspicious. This technique examines the mole’s color patterns and other details. However, we don’t yet have a set of widely accepted rules to determine if an atypical mole might be a melanoma, based on the dermoscopy exam.
Through dermoscopy, atypical moles can be classified into different subtypes:
- Reticular subtype: The most common form, with a clear pattern of dark brown lines spread evenly across the mole and fading towards the edges.
- Globular subtype: Recognized by a pattern of “speckled” dots spread within the mole.
- Homogenous subtype: The rarest form, with mixed shades of brown throughout the mole.
- Mixed: Moles showing both reticular and globular patterns have to be examined very carefully because it could mean they’re a melanoma.
In conclusion, professional evaluation is essential for any suspicious moles, particularly if they display characteristics of multiple subtypes.
Treatment Options for Atypical Mole
There is no known way to prevent the formation of atypical moles. However, if you have a history of these moles, it is particularly important for you to use strong sun protection. Regular skin checks by a healthcare professional are recommended. They can look at any moles that you’re worried about and monitor any changes in existing ones. This is considered the best way to detect skin cancer early.
Doctors have differing views regarding the best way to manage atypical moles. If there are any concerns about new or changing atypical moles, a biopsy (removal for testing) is usually performed. The American Academy of Dermatology found that the majority of doctors they surveyed would perform a second removal if the margins of the mole were not fully removed or the mole reappeared. This procedure is performed due to the risk that a recurring mole along a scar may look like skin cancer, a phenomenon known as ‘pseudo-melanoma’.
However, there is a significant amount of evidence suggesting that most atypical moles need not be removed a second time. Exceptions to this include cases where the physical examination and the laboratory tests do not match, the mole is severely atypical, or the mole cannot be definitively identified as non-cancerous. In these cases, the mole should be treated according to guidelines for managing skin cancer and removed with sufficient margins.
What else can Atypical Mole be?
When a doctor is trying to identify an unusual mole, the main condition they consider is melanoma, which often appears in a form known as superficial spreading melanoma. A dermatoscope, a tool used to examine skin, can help distinguish between this type of melanoma and unusual moles. However, when there’s doubt or concern, doctors should handle these suspicious skin changes according to the procedures and guidelines set for treating melanoma.
Moles present at birth, known as congenital nevi, typically have a larger size and noticeable hair, features usually not seen in unusual moles. Another skin condition, seborrheic keratosis, can occasionally be mistaken for an unusual mole. However, its dull surface and a thickening of the skin, called hyperkeratosis, should guide doctors to the correct diagnosis in most situations.
Possible Complications When Diagnosed with Atypical Mole
A small number of unusual moles can develop into melanoma, a type of skin cancer. This is why these moles are important to track closely. In general, people in the United States have less than a 1% chance of getting melanoma. However, if you have atypical moles, your risk increases to more than 10%. Comparatively, the chance of a regular mole turning into melanoma is quite low, with rates of 1 in 30,000 for men and 1 in 40,000 for women.
Most atypical moles (75%) appear without any previous mole in that spot. A particular group of people who are at a very high risk are those with a condition known as familial atypical multiple-mole melanoma syndrome (FAMMM). These individuals virtually all face the danger that their atypical moles will change into melanoma.
Preventing Atypical Mole
Regular self-checks of your whole body can help spot unusual skin moles early, and track any changes they might have. You can get help with this from your doctor, who you should ideally see every 4 to 6 months, especially if you have a high risk of skin issues. Having your moles photographed regularly can also help in noticing any changes.
It’s crucial for everyone to know how important it is to apply a good amount of high factor sun protection cream. This can decrease the chance of getting different types of skin cancer. Health professionals should always recommend the use of sun protection to all their patients.
