Very few moles actually require medical treatment, but a mole that is evolving in shape, size, texture or color could be indicative of a cancerous growth. The providers at Knoxville Institute of Dermatology are experts in assessing all types of moles. If you have a mole that displays any of these type of changes contact our office today for an evaluation.
What is a mole?
A mole is a common benign skin lesion due to a local proliferation of pigment cells (melanocytes). It is more correctly called a melanocytic nevus, and is sometimes also called a naevocytic nevus. A brown or black mole contains the pigment melanin, so may also be called a pigmented nevus. A mole can be present at birth (congenital nevus) or appear later (acquired nevus). There are various kinds of congenital and acquired nevi.
Who gets moles?
Almost everyone has at least one mole.
- About 1% of individuals are born with one or more congenital melanocytic nevi. This is usually sporadic, with rare instances of familial congenital nevi.
- Fair-skinned people tend to have more moles than darker skinned people.
- Moles that appear during childhood (aged 2 to 10 years) tend to be the most prominent and persistent moles throughout life.
What causes moles?
Although the exact reason for local proliferation of nevus cells is unknown, it is clear that the number of moles a person has depends on genetic factors, on sun exposure, and on immune status.
- People with many moles tend to have family members that also have many moles, and their moles may have a similar appearance.
- New melanocytic nevi may erupt following the use of BRAF inhibitor drugs (vemurafenib, dabrafenib).
- Immunosuppressive treatment leads to an increase in numbers of nevi.
What are the clinical features of moles?
Moles vary widely in clinical, dermatoscopic and histological appearance.
- They may arise on any part of the body.
- Moles differ in appearance depending on the body site of origin.
- They may be flat or protruding.
- They vary in color from pink or flesh tones to dark brown, steel blue, or black.
- Light skinned individuals tend to have light-colored moles and dark skinned individuals tend to have dark brown or black moles.
- Although mostly round or oval in shape, moles are sometimes unusual shapes.
- They range in size from a couple of millimeters to several centimeters in diameter.
What are the complications of moles?
People worry about moles because they have heard about melanoma, a malignant proliferation of melanocytes that is the most common reason for death from skin cancer.
- At first, melanoma may look similar to a harmless mole, but in time it becomes more disordered in structure and tends to enlarge.
- People with a greater number of moles have a higher risk of developing melanoma than those with few moles, especially if they have over 100 of them.
Moles sometimes change for other reasons than melanoma, for example following sun exposure or during pregnancy. They can enlarge, regress or involute (disappear).
- A Meyerson nevus is itchy and dry because it is surrounded by eczema.
- A Sutton or halo nevus is surrounded by a white patch, and fades away over several years
- A recurrent nevus is one that appears in a scar following surgical removal of a mole — this may have an odd shape.
How is a mole diagnosed?
Moles are usually diagnosed clinically by their typical appearance. If there is any doubt about the diagnosis, an expert may be consulted in person or with the help of clinical and dermatoscopic images. This is especially important if:
- A mole changes size, shape, structure or color
- A new mole develops in adult life (> 40 years)
- It appears different from the person’s other moles (a so-called ugly duckling)
- It has ABCD characteristics (Asymmetry, Border irregularity, Color variation, Diameter > 6 mm)
- It is bleeding, crusted or itchy
Most skin lesions with these characteristics are actually harmless when evaluated by an expert using dermatoscopy. Short-term digital dermatoscopic imaging may be used in equivocal flat lesions to check for change over time.
Nevi that remain suspicious for melanoma are excised for histopathology (diagnostic biopsy). Partial biopsy is not recommended, as it may miss an area of cancerous change.
What is the treatment for moles?
Most moles are harmless and can be safely left alone. Moles may be removed in the following circumstances:
- To exclude cancer
- The mole is a nuisance: perhaps irritated by clothing, comb or razor
- Cosmetic reasons: the mole is unsightly
Surgical techniques include:
- Excision biopsy of flat or suspicious mole
- Shave biopsy of protruding mole