What Are the Signs of a Cancerous Mole?

Moles are pretty common, and most of the time, they’re nothing to worry about. That doesn’t mean you can ignore them, though.

You’ve got to keep an eye on them because some are more than just harmless skin marks. Moles can be a precursor to melanoma, a severe form of skin cancer, so it’s best to know what to look for in a mole.

Dr. Robert Topham and our Holladay Dermatology & Aesthetics team explain the signs of cancerous moles using the alphabet. The ABCDEs of mole assessment help you spot the warning signs, and knowing what to look for can be a lifesaver, literally. 

Mole basics

Moles,also called nevi, are skin growths that appear anywhere on your body, alone or in groups. Most people have between 10 and 40 moles by adulthood, and typically, they appear during childhood and adolescence.

Moles are generally harmless. They’re clusters of pigmented cells called melanocytes. However, when these cells begin to grow and multiply uncontrollably, they can become cancerous, so it’s important to monitor your moles regularly.

Following the ABCDEs can help you identify suspicious moles. Dermatologists developed this method to help people spot warning signs of melanoma, the deadliest form of skin cancer. 

A is for asymmetry

A harmless mole is symmetrical, meaning if you draw a line through the middle, both halves will match. If one half of the mole doesn’t match the other, it’s asymmetrical, which could be a warning sign.

Asymmetry occurs when the growth of melanocytes becomes uneven, a characteristic of melanoma. When examining your moles, use a mirror or ask a friend to help you check for symmetry on hard-to-see areas like your back.

Not all asymmetrical moles are cancerous, but if you notice a mole’s shape changing over time, it’s worth having Dr. Topham check it out. 

B is for border

Harmless moles usually have smooth, even edges. Moles with irregular, scalloped, or poorly defined borders may be a cause for concern. Jagged edges can indicate uncontrolled cell growth.

Irregular borders mean that the cells are growing beyond their typical confines, which could suggest that they’re invading adjacent skin tissue, a characteristic of melanoma. 

C is for color

Healthy moles are usually a single shade of brown. A mole showing different colors, such as tan, black, red, white, or blue, could indicate an abnormality.

When melanocytes mutate into cancerous cells, they can produce different pigments, leading to a varied appearance. This is why a mole that has multiple colors might mean melanoma. 

While color changes can be a warning sign, they aren’t definitive proof of cancer. 

D is for diameter

Malignant moles are often larger than benign ones. We typically consider moles larger than 6 millimeters, about the size of a pencil eraser, potentially suspicious.

However, melanoma can be smaller when first detected. This means that size alone isn’t a definitive indicator of a cancerous mole. We always consider diameter in conjunction with other symptoms when evaluating your moles.

E is for evolving

Any changes in size, shape, color, or sensation, such as itching or tenderness over time, could indicate a problem. Moles that evolve are more likely to be malignant.

Melanoma is known for changing rapidly, so regular self-examinations help you detect any alterations early on. Record your moles and note any transformations you observe, or use a mole-tracking app.

When to see us about a mole

While the ABCDEs are helpful, they aren’t a substitute for Dr. Topham’s professional medical advice. If you notice any signs of a suspicious mole, call us so we can conduct a thorough examination and provide an accurate diagnosis.

If you spot something concerning, don’t wait until your annual skin check-up. Melanoma develops quickly, so come to see us as soon as possible. 

Myths about moles

Many misconceptions surround moles and skin cancer. 

Myth #1: All moles are dangerous

In reality, most moles are harmless and stay the same throughout your life. 

Myth #2: Only fair-skinned people need to worry about skin cancer

While fair skin is a risk factor, melanoma can affect anyone, regardless of skin color.

Myth #3: Only new moles can be cancerous

While new moles should be monitored, existing moles can also become cancerous, which is why it is so important to track changes in your moles over time.

If you have suspicious moles, call Holladay Dermatology & Aesthetics in Salt Lake City, Utah, to schedule a skin check with our mole experts.