Moles or nevi: everything you need to know

Moles or nevi:
the differences and recognition

Moles are skin spots caused by the accumulation of melanocytes, which are the cells that produce melanin. Melanin is the pigment that protects us from the sun by tanning.
Melanocytes are usually evenly distributed in the skin, but moles occur when the cells accumulate and grow together in clusters.

Differences in moles

The appearance of moles will change depending on the number of melanocyte cells in them, how much melanin they produce and how deep they are.
Moles can be small and round, or larger and more jagged. They can be flat to the skin, or can grow outward like a dome; they can be smooth or wrinkled, and can be hairless or have hair. The amount of variety that can occur with moles can surprise even dermatologists!

Benign or malignant moles

While moles can come in all shapes and colors, it is very important to classify them due to the risk that some can develop into melanoma, a malignant tumor. For the most part, moles are benign and are usually, at worst, aesthetic concerns that are, for example, simply too large, too dark, too numerous or too prominent, but nothing more.

Recognition

While not always easy to do, recognising moles that are benign from those that are potentially malignant can help to focus attention on areas that need it most.

Classification of moles by name

Moles are categorized and named after the researcher or physician who first described them.

Miescher nevi

Miescher nevi are moles that occur on the face. They grow in the shape of a dome and can be either dark or flesh-colored. Some are smooth, while others may be more uneven and some may have one or more hairs coming out of it.
They are very common and are especially noticeable if they grow on the nose, forehead or chin. Miescher nevi can also be particularly noticeable if there are protruding hairs. They are benign, however they sometimes cause concern among those unfamiliar with them, to the extent that some people try to cut them with razors or try to pluck the hair with tweezers. Fortunately, nothing serious happens, but such actions damage the skin and are painful.

Unna nevi

Unna nevi are as frequent as Miescher nevi, but develop on the trunk and are especially common on the abdomen or back. They are easy to recognize as they characteristically grow outward in the shape of a blackberry. Unna nevi are also benign but can cause both functional and cosmetic issues due to the fact they can be quite large, can be numerous and can grow at sides of potential trauma such as the girdle or armpits.

Common moles

As the name suggests, common moles are the most commonly found type of nevi and can be found almost anywhere on the skin. They are usually dark, roundish spots, but can become atypical (Clark nevus) whereby they will be larger, more pigmented or show signs of irregularity.

Atypical moles (Clark’s nevus)

Atypical moles are characterized by a diameter greater than 6 mm, uneven color and irregular borders. They are present on both the trunk and limbs, and some individuals will have many of them. These moles have a greater risk of evolution into melanoma, so should be monitored by the dermatologist with mapping and dermatoscopic examinations. Where necessary, these moles may need to be surgically removed.

Spitz nevi

Spitz nevi often develop in children or adolescents. They are very dark in color, grow rapidly and usually appear on the limbs or, sometimes, the face. Although they are also benign, due to the rate at which they grow and how suspicious-looking they are, many individuals become worried about melanoma and have the moles surgically removed.

Reed nevi

Reed nevi are the equivalent of Spitz nevi in adults. They most often occur on the limbs of young women. They, too, are benign but are often surgically removed due to their rapid growth and dark color.

Halo moles

Halo moles are common moles that frequently form in adolescence. The moles are surrounded by a white ring of vitiligo, both of which slowly fade, shrink and then completely disappear over time. These progressively regressive moles are not dangerous.

Conclusion

The classification of moles by the names above is a universally-accepted means of recognition that allows dermatologists to understand one another. It also helps individuals to understand whether their moles are at-risk, or whether they are simply nothing more than a cosmetic mark.