The Common Mole.
How do you spot a harmless one?
How do you spot a harmless one?
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.
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.
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:
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!
There are several different types of moles including:
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 nevi moles usually appear at birth or in infancy.
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.
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:
Melanoma may develop from a mole – although it’s more common for a melanoma to develop spontaneously.
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.
Moles are the most common of the benign lesions.
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