Melanocytic naevus (mole)

Melanocytic naevus (common name: mole) is a very common skin benign lesion that results from the rapid growth of melanocytes (pigmented cells). The exact reason why moles appear is still unknown, but the number of moles on one’s body depends on various factors, such as genetic predisposition, immune status, or prolonged sun exposure.  Melanocytic naevus can be already present since birth. In medical dermatology, it carries a term “congenital naevus. About 1% of the population is born with one more moles. Or, moles can appear during the lifespan. They carry a term “acquired naevus.”

Generally, individuals with lighter skin tones are predisposed to having more moles than dark skinned individuals. People who have many moles usually have family members who share the same trait. Moreover, there is a phenomenon when individuals who undergo immunosuppressive treatment would have increase in mole numbers as one of the side effects.

In medical dermatology, moles have a distinct dermatoscpic and histological appearance. Moles can be flat or protruding. They can appear on any part of the body; the origin of body part will determine the overall appearance of this lesion. Moles also vary in color: ranging from pink to black. Individuals with lighter skin usually have light-colored moles. Individuals with darker skin have dark brown or black moles. Moles can also vary in size: ranging from a few millimeters to a few centimeters in diameter. Lastly, they usually have a roundish shape, but there are rare cases when the shape is quite irregular. 

Regardless of its common presence on human bodies and their benign nature, melanocytic naevi can be mimicked by the melanoma, which is one of the deadliest skin cancer. Initially, melanoma may look like a regular mole, but eventually, it leads to an enlargement in size as well as to more irregular shape change. Moreover, individuals who have quite a big number of moles on their bodies can be at a higher risk of developing melanoma.

In clinical practice, dermatologists access moles by their appearance through dermatoscopy. This is a tool for skin examination that uses skin surface microscopy to examine the structure and patterns of patient’s skin. The following ques are: change in size, colour, shape, and/or structure of a mole. Patients who have new moles formed after age of 40 are at the risk of developing melanoma. Melanocytic naevus can also fall under ABCD analysis: Asymmetry, Border irregularity, Colour variation, Diameter (when greater than 6 mm). Lastly, moles that are itchy, cause bleeding, or appear crusty are indications for potential more detailed assessment. If nevi appear to be suspicious for melanoma, the dermatologist will perform a diagnostic biopsy (taking a tissue sample for histopathology). This technique involves the excision (complete removal) or incision/punch biopsy (taking a small portion) or of the affected skin tissue for further laboratory analysis.

Melanocytic naevus is usually only removed in cases of suspected cancer, and for cosmetic purposes. The surgical removal techniques involve the excision biopsy if the mole is flat or shave biopsy if the mole is protruding. A mole can also be removed with radiofrequency surgery. If there is indication for the mole removal, the Dermatologist will descuss the best option dor removal with minimu scarring.

Centre for Medical and Surgical Dermatology offers various treatment options of Melanocytic naevusthat are individual for each patient. For more information, visit the following link: 

Surgical Dermatology

To learn more about dermato-oncology and all treatment methods offered by Centre for Medical and Surgical Dermatology, visit the following link:

Dermato-oncology