Table of ContentsView AllTable of ContentsSymmetryBordersColorDiameterEvolutionDysplastic Nevi
Table of ContentsView All
View All
Table of Contents
Symmetry
Borders
Color
Diameter
Evolution
Dysplastic Nevi
Identifying moles vs. skin cancer is not always easy. However, there are telltale signs that can help differentiate a benign (non-cancerous) skin lesion from potentially dangerousskin cancer.
Benign molescome in various shapes, sizes, and colors (e.g., pink moles, brown moles, flat moles, raised moles, etc.), but are usually round with smooth edges.
When checking for early signs of a potential melanoma it’s helpful to use theABCDE rule, which stands for:
Marie Wurm / Getty Images
What Moles Look Like
This is an example of a normal mole. Note that it is almost perfectly round.
A mole is a benignmelanocytictumor, meaning a non-cancerous skin lesion that develops from pigment-producing cells calledmelanocytes.
Also known as nevus (singular) and nevi (plural), moles are not usually present at birth but begin to appear during childhood and the teen years. They can either develop on the top layer of skin (epidermis) or just under the skin (dermis).
What Melanoma Looks Like
Here is an example of melanoma. Melanoma differs in that the lesions are usually asymmetrical (lopsided).
Melanoma is a type of skin cancer that also develops from pigment-producing melanocytes. The primary cause of melanoma is overexposure to ultraviolet (UV) radiation from the sun or tanning beds.
Melanoma is the most dangerous type of skin cancer, affecting more than 230,000 people globally and causing over 50,000 deaths each year. In the United States, males are about 1.5 times more likely to get melanoma than females.
Normal moles generally have well-defined borders along with uniform color. They can either be raised or flat (as pictured).
Despite variations in size or color, the vast majority of moles have smooth borders that are clearly separate from the surrounding skin. The color of the mole will typically be even rather than mottled.
This melanoma tumor has a border that is uneven, ragged, and notched. The color also appears to “bleed” around the edges.
An uneven, jagged border is one of the tell-tale signs of melanoma. By contrast, moles tend to have smoother, more even borders.
While about 20%-30% of melanomas develop in existing moles, 70%-80% arise on seemingly normal skin.
Moles vary in color. Some may be pink or flesh-colored, while others may be tan or brown (as pictured). Some can be small and freckle-like, while others may look like a Cindy Crawford-style beauty mark.
Moles can change in color without becoming cancerous. For example, moles on the face will often start as brown but get lighter or darker with age.Moles can also raise or flatten (though they typically remain the same size).
In addition to asymmetry, uneven coloration is a hallmark of melanomas. The same lesion can have a range of colors, from tan, orange, and brown all the way to red, black, and blue.
Another clue that a person has melanoma is the so-called “ugly duckling sign.”
By and large, the moles on a person’s body will all look the same. However, if you step back and look at them in their entirety, there may be some that stand out as being different, either in terms of color, size, or shape.
These “ugly ducklings” may be an early sign of melanoma.
Some moles may be bigger than others, but most are around 1 to 2 millimeters in diameter. On occasion, a mole may be up to 5 millimeters in diameter (1/5 inch), but this is rare.
Most moles never cause any problems, but, ironically, a person who has more than 50 has a higher risk of developing melanoma. These moles, called acquired moles, appear on the skin after birth (unlike congenital moles you are born with).
Most people have between 10 and 40 acquired moles on their body.Having a higher number warrants an annual check-up to examine parts of the body you cannot readily see, like your back and back of your neck.
Any mole over 6 millimeters (1/4 inch) in diameter should be looked at. Melanomas can be tiny, but most are larger than the size of a pea or pencil eraser.
The one pictured here is significantly larger.
In addition to the diameter of a lesion, the thickness of a lesion is also a red flag. With melanoma, the thicker the tumor, the poorer the outcome (prognosis).
Melanoma that is less than 1 millimeter thick has a low risk of spreading to other parts of the body. Melanoma thicker than 4 millimeters not only have a high risk of spreading (metastasizing) but also a high risk of returning (recurring) aftertreatment.
A mole really doesn’t change if you have one. While some may get a bit darker as you age, they will usually remain the same color, size, and shape.
This includes dermal nevi (pictured) that match the skin color of the surrounding skin.
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Any changes in the color, size, or shape of a mole should be investigated. This includes changes in texture, such as sudden flaking or scaliness.
This includes changes like:
The challenge, of course, is recognizing the changes. Unless you do a regular self-examination, you may not even notice a mole has changed unless it is bleeding or has caused a skin ulcer. This is especially true if you have lots of moles.
The Skin Cancer Foundation is among the organizations that endorse once-yearly skin exams.
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Understanding Dysplastic Nevi
There are atypical moles, also calleddysplastic nevi. These are often larger, oddly shaped, oddly textured, and multi-colored but are not considered cancerous.
Cells from a dysplastic nevus don’t look completely normal under a microscope and may display some features resembling early-stage melanoma. However, these cells don’t have the features that make them cancerous. Dysplastic nevi rarely become cancerous.
Summary
Moles and melanoma can be hard to tell apart. Dermatologists use a system called the ABCDE rule as a guideline for identifying cancerous lesions. ABCDE stands for asymmetry, border, color, diameter, and evolving.
These signs can help spot skin cancer early when it is still highly treatable. In addition to doing regular self-exams at home, an annual, full-body checkup with a dermatologist is often recommended.
12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Daniel Jensen J, Elewski BE.The ABCDEF rule: Combining the “ABCDE rule” and the “ugly duckling sign” in an effort to improve patient self-screening examinations.J Clin Aesthet Dermatol.2015;8(2):15.McCourt C, Dolan O, Gormley G.Malignant melanoma: a pictorial review.Ulster Med J. 2014;83(2):103-10.Black S, Macdonald-McMillan B, Mallett X, Rynn C, Jackson G.The incidence and position of melanocytic nevi for the purposes of forensic image comparison.Int J Legal Med.2014;128(3):535-43. doi:10.1007/s00414-013-0821-zAmerican Academy of Dermatology Association.Skin Cancer - Incidence rates.UnityPoint Health.3 Types of Skin Moles.The Skin Cancer Foundation.Melanoma Warning Signs.National Cancer Institute.Common Moles, Dysplastic Nevi, and Risk of Melanoma - What is a common mole?American Cancer Society.Melanoma Skin Cancer Stages.Centers for Disease Control and Prevention.What Are the Symptoms of Skin Cancer?Skin Cancer Foundation.Annual Exams: Five Easy Steps to Prepare Yourself.Sung WW, Chang CH.Nevi, dysplastic nevi, and melanoma: molecular and immune mechanisms involving the progression.Tzu Chi Med J. 2021;34(1):1-7. doi:10.4103/tcmj.tcmj_158_20National Cancer Society.Can a dysplastic nevus turn into melanoma?
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Daniel Jensen J, Elewski BE.The ABCDEF rule: Combining the “ABCDE rule” and the “ugly duckling sign” in an effort to improve patient self-screening examinations.J Clin Aesthet Dermatol.2015;8(2):15.McCourt C, Dolan O, Gormley G.Malignant melanoma: a pictorial review.Ulster Med J. 2014;83(2):103-10.Black S, Macdonald-McMillan B, Mallett X, Rynn C, Jackson G.The incidence and position of melanocytic nevi for the purposes of forensic image comparison.Int J Legal Med.2014;128(3):535-43. doi:10.1007/s00414-013-0821-zAmerican Academy of Dermatology Association.Skin Cancer - Incidence rates.UnityPoint Health.3 Types of Skin Moles.The Skin Cancer Foundation.Melanoma Warning Signs.National Cancer Institute.Common Moles, Dysplastic Nevi, and Risk of Melanoma - What is a common mole?American Cancer Society.Melanoma Skin Cancer Stages.Centers for Disease Control and Prevention.What Are the Symptoms of Skin Cancer?Skin Cancer Foundation.Annual Exams: Five Easy Steps to Prepare Yourself.Sung WW, Chang CH.Nevi, dysplastic nevi, and melanoma: molecular and immune mechanisms involving the progression.Tzu Chi Med J. 2021;34(1):1-7. doi:10.4103/tcmj.tcmj_158_20National Cancer Society.Can a dysplastic nevus turn into melanoma?
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Daniel Jensen J, Elewski BE.The ABCDEF rule: Combining the “ABCDE rule” and the “ugly duckling sign” in an effort to improve patient self-screening examinations.J Clin Aesthet Dermatol.2015;8(2):15.McCourt C, Dolan O, Gormley G.Malignant melanoma: a pictorial review.Ulster Med J. 2014;83(2):103-10.Black S, Macdonald-McMillan B, Mallett X, Rynn C, Jackson G.The incidence and position of melanocytic nevi for the purposes of forensic image comparison.Int J Legal Med.2014;128(3):535-43. doi:10.1007/s00414-013-0821-zAmerican Academy of Dermatology Association.Skin Cancer - Incidence rates.UnityPoint Health.3 Types of Skin Moles.The Skin Cancer Foundation.Melanoma Warning Signs.National Cancer Institute.Common Moles, Dysplastic Nevi, and Risk of Melanoma - What is a common mole?American Cancer Society.Melanoma Skin Cancer Stages.Centers for Disease Control and Prevention.What Are the Symptoms of Skin Cancer?Skin Cancer Foundation.Annual Exams: Five Easy Steps to Prepare Yourself.Sung WW, Chang CH.Nevi, dysplastic nevi, and melanoma: molecular and immune mechanisms involving the progression.Tzu Chi Med J. 2021;34(1):1-7. doi:10.4103/tcmj.tcmj_158_20National Cancer Society.Can a dysplastic nevus turn into melanoma?
Daniel Jensen J, Elewski BE.The ABCDEF rule: Combining the “ABCDE rule” and the “ugly duckling sign” in an effort to improve patient self-screening examinations.J Clin Aesthet Dermatol.2015;8(2):15.
McCourt C, Dolan O, Gormley G.Malignant melanoma: a pictorial review.Ulster Med J. 2014;83(2):103-10.
Black S, Macdonald-McMillan B, Mallett X, Rynn C, Jackson G.The incidence and position of melanocytic nevi for the purposes of forensic image comparison.Int J Legal Med.2014;128(3):535-43. doi:10.1007/s00414-013-0821-z
American Academy of Dermatology Association.Skin Cancer - Incidence rates.
UnityPoint Health.3 Types of Skin Moles.
The Skin Cancer Foundation.Melanoma Warning Signs.
National Cancer Institute.Common Moles, Dysplastic Nevi, and Risk of Melanoma - What is a common mole?
American Cancer Society.Melanoma Skin Cancer Stages.
Centers for Disease Control and Prevention.What Are the Symptoms of Skin Cancer?
Skin Cancer Foundation.Annual Exams: Five Easy Steps to Prepare Yourself.
Sung WW, Chang CH.Nevi, dysplastic nevi, and melanoma: molecular and immune mechanisms involving the progression.Tzu Chi Med J. 2021;34(1):1-7. doi:10.4103/tcmj.tcmj_158_20
National Cancer Society.Can a dysplastic nevus turn into melanoma?
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