The Common Mole.

How do you spot a harmless one?

What is a mole?

A mole (nevus or naevus) is a benign “nest” of melanocytes, which are cells that produce melanin, the pigment that causes skin colour. Looking closely at each mole is a crucial part of a skin check.

Who gets them?

Everyone has moles. In fact, your moles were probably determined before you were born. Typically, they appear in childhood but may also appear throughout your life, particularly during times of hormonal changes.

What does Mole look like?

A Mole to the Naked Eye

A mole is basically a gathering of melanocytes, the pigment-forming cells of the epidermis or upper layer of skin. These nests come in a bewildering variety and the easiest way to classify them is by the position of the nests within the skin. The nests can be superficial, deep, or a mixture of the two and include:

Junctional Nevus: These nests occur at the junction between the epidermis and dermis and are usually flat and brown.
Dermal Nevus: These occur in the dermis, which is a lower level of the skin and can be raised, pink, skin coloured or brown. This type of mole often has hairs growing from it. Dermal nevi moles on the face are called Miescher Nevus, and on the body they’re called Unna Nevus.
Compound Nevus: These moles are what they sound like, they’re basically a combination of the previous two and occur between and in the epidermis and dermis.

A mole can generally be identified as Junctional, Dermal or Compound by its dermoscopic appearance. A biopsy would confirm the diagnosis. All that matters is that the mole is not a melanoma!

Mole Types

There are several different types of moles including:

Congenital Moles, which are present at birth or early childhood and tend to become raised and roughened with age, much like a dermal nevus.
Blue nevus , which is dark blue, almost black in colour
Atypical Mole, which is also called Dysplastic Nevus, and may look very much like a melanoma
Halo Nevus, which has a ‘halo’ around it, suggesting that the immune system is ‘getting rid of it’
Recurrent nevus, which are moles that have been previously cut-out and come back such as after a shave biopsy
Speckled Lentiginous Nevus, which have a speckled appearance and are usually large and flat.
Spitz nevus, a dangerous kind of mole that usually requires a biopsy to rule out melanoma.
Labial Melanotic Nevus, which is a benign mole on the lip.

What do the different types of Moles look like?

The appearance of a mole depends on whether it is junctional (flat & involving only a thin upper layer of skin), dermal (thick & involving deeper layers of skin) or compound (in-between).

This is why your moles may all look so different to each other.

Flat Moles (Junctional Nevi)

Thick moles (Dermal Nevi)

Compound Moles

These are a combination of the above two types of mole (Junctional and Dermal moles). They are often a little raised and dark and can look like a melanoma more than other types do.

Congenital moles

Congenital nevi moles usually appear at birth or in infancy.

Acral Moles (on the palms or soles)

Other types of mole

Here you have some Speckled Nevus moles, which are just what they sound like, and some recurrent nevis, which are moles that regrow after incomplete removal.

Why Do Moles Matter?

Facts about Moles and Melanoma

If everyone has moles, then you might wonder why they matter. While it’s true that most moles are harmless, here are some less benign facts about them:

Moles change in appearance with age – and can develop into melanoma
The greater the number of moles, the greater the risk of melanoma, especially if you have more than 100 moles
Melanoma can develop from a simple, benign mole – but it’s more common for a melanoma to develop spontaneously
Moles usually grow in childhood and early adulthood and if you see a new mole on your skin when you’re over 40 it could be a melanoma

Some people have so many moles that they need a very thorough skin check to find dangerous ones
A melanoma starts out looking like a mole and can be tiny
Moles usually start flat and become thicker and darker with age – leading to concerns about melanoma and cosmetic concerns

Melanoma may develop from a mole – although it’s more common for a melanoma to develop spontaneously.

Pathology Report

The Mole Pathology Report

If you have to get a mole removed and biopsied, then you will get a Pathology Report telling you about the findings. A nevus is only removed for either cosmetic concerns or to exclude a melanoma (or other type of skin cancer).

Within a nevus, the melanocytes (pigment forming cells) are grouped together in “nests.”

Junctional Nevus

In a junctional nevus, the nests are located along the base of the epidermis.

Compound Nevus

The melanocyte nests are found both in the lower layer of the epidermis (as for a junctional nevus) and also the dermis (as for a dermal nevus) – it’s basically a combination of junctional & dermal.

Dermal Nevus

The nests of melanocytes are found in the dermis ie. in the deeper layer of skin than with a junctional nevus.

Dysplastic Nevus

Dysplasia is an important term in pathology reports. Dysplastic melanocytes look abnormal in some way.

The cells may have a nucleus that’s abnormal in shape and colour. The nuclei may be angulated, a darker colour (hyperchromasia), or it may nucleoli may be prominent. There may also be bridges between epidermal projections, which are finger-like projections into the epidermis from the layer below, or even some fibrosis (scar-like tissue).

If the pathologist can’t tell a lesion from a melanoma, then it’s called a severely dysplastic nevus.

Good Lesions

Moles are the most common of the benign lesions.