Introduction: “Doctor, I have a mole here, it’s dark and hairy, should I remove it?” Such a question is often encountered in clinical work. What kind of moles have the possibility of malignant transformation? And what kind of moles need to be removed?
Moles, medically known as pigmented moles, are benign neoplasms composed of nevus cells, which can occur in almost everyone, from infants to the elderly, and their number increases with age, often increasing significantly during puberty.
Clinically, some patients may ask, “Why do my moles look more than others? The number of moles is mainly determined by genetics. Generally speaking, women have more moles than men, and whites have more moles than blacks. Pigmented nevus is a developmental abnormality, which is a localized aggregation of melanocytes caused by various factors.
The basic damage of pigmented nevus is usually a rash, papule or nodule, brown, brown, blue-black, black, dark red, etc., round, with clear border and smooth surface. Sun exposure can increase the number of pigmented nevi in exposed areas. Medically, according to the distribution of nevus cells, there are three kinds of nevus: junctional nevus, intradermal nevus and mixed nevus.
Junctional nevus
They are usually small, 1~6 mm in diameter, smooth, hairless, flat or slightly above the skin surface, and light to dark brown in color. It can occur on any part of the body.
Mixed nevus
Similar in appearance to junctional nevi, but may be more prominent, sometimes with hair penetration, most often seen in children and adolescents.
Intradermal nevus
Common in adults, they are hemispherical raised papules or nodules, a few millimeters to centimeters in diameter, with a smooth or papillary surface, or with a tip, and may contain hairs. Intradermal nevi usually do not increase in size. They are mostly found on the head and neck.
Pigmented nevi are unstable and often undergo a growth and evolution process from maturation to aging. At first, they are mostly small and flat nevi, but later they mostly develop into mixed nevi and finally into intradermal nevi.
Junctional nevus has a higher possibility of malignant transformation. When malignant transformation occurs, there will be local discomfort, mild pain, burning or stinging, satellite dots at the edges, such as sudden enlargement, color deepening, inflammatory reactions such as redness around the nevus, and when it breaks or bleeds, we should be alert.
In clinical work, pigmented nevi need to be distinguished from malignant melanoma, which is a tumor with a high degree of malignancy. In general, malignant melanoma is often asymmetrical, with unclear borders, non-smooth edges, uneven color, rapid tumor development, and easy rupture and bleeding. It is important to note that clinical presentation is not the gold standard.
In our work, we have encountered “moles” that look like benign manifestations such as “wart”, but the pathology shows that they are melanoma. Therefore, it is still necessary to have the help of a specialist and, if necessary, biopsy and pathological tissue examination to make a clear diagnosis. In addition, it should be differentiated from seborrheic keratosis, dermatofibroma, pigmented basal cell carcinoma and other diseases.
Which “moles” should be alerted
Moles that are clearly diagnosed generally do not require treatment except for cosmetic needs.
Pigmented nevi that occur in the palmoplantar, waistline, armpit, groin, shoulder and other friction-prone areas should be closely observed.
Some damages with irregular edges, uneven color and diameter ≥ 1.5 cm should be paid more attention
Once rapid expansion or partial elevation or rupture and bleeding are found, they should be removed promptly.
Note: Pigmented nevi are generally not treated with laser unless the lesions are very small and superficial, because if the treatment is not complete, the residual nevus cells are prone to recurrence.