What are Skin Moles

Skin Moles are benign neoplasms of melanocytes. Junctional Skin Moles are localized collections of neval melanocytes found in the epidermis and superficial dermis, they are flat and pigmented. Compound Skin Moles are localized collections in the epidermis and superficial and deep dermis, these Skin Moles are pigmented and raised. Intradermal Skin Moles are localized collections in the deep dermis with no involvement of the epidermis or junctional dermis, such Skin Moles are flat and flesh-colored. Most Skin Moles are absent at birth. They tend to first appear and increase in number during childhood, reaching their maximum in early adulthood. Skin Moles counts have been shown to increase at an earlier age in Caucasians who live closer to the equator, where sun exposure and intensity is greatest.
Large numbers of Skin Moles, both common acquired Skin Moles and atypical Skin Moles, are markers of individuals who are susceptible to developing melanoma. Atypical Skin Moles are large (+6 mm) compound Skin Moles often with a surrounding macular erythematous component, irregular in color or shape, but nevertheless benign. These lesions may or may not show histological evidence of dysplasia, therefore the old term ‘dysplastic Skin Moles’, which leads to much confusion, is not recommended. Although the clinical differentiation of atypical Skin Moles from melanoma is difficult, it may be facilitated by regular surveillance and clinical photography. The presence of more than five atypical skin moles on a person has been shown to be a powerful and independent marker of melanoma susceptibility.
‘Congenital Skin Moles’ is a term applied both to compound Skin Moles present at birth and to acquired Skin Moles that are clinically and histologically similar to skin moles present at birth. One child in 100 is born with a congenital pigmented nevus, while 6 to 12 per cent of children and adults have a ‘congenital type nevus’. The risk of evolution of a small congenital nevus (-2 cm) into invasive melanoma is unknown, but is thought to be much less than 1 per cent. Prophylactic excision is not universally advocated, but rather considered on a case-by-case basis. Large congenital Skin Moles (20 cm) occur in 1 in 500 000 births and probably carry a 4 to 6 per cent risk of progression to melanoma over a lifetime. The melanoma usually develops after puberty and does not always occur in the nevus itself. Unfortunately, removal of large lesions is rarely easy and may involve numerous surgical procedures.
There may be a natural evolution of acquired Skin Moles from junctional to compound to intradermal Skin Moles. The malignant potential of individual lesions is low, therefore prophylactic excision of acquired Skin Moles to prevent transformation into melanoma is not advised. Most melanomas arise de novo in the absence of any clinical or histological evidence of a pre-existing nevus. Excision of Skin Moles is advocated where it is not possible to clinically exclude a diagnosis of melanoma. The lesion should be totally excised and submitted for histological assessment. Destructive therapy of Skin Moles without histological assessment is a recipe for disaster, for clinical diagnosis is not completely accurate and an opportunity to re-excise an incompletely or inadequately removed tumor may be missed. Patients who subsequently present with metastatic melanoma without an identified primary will rightly or wrongly point the finger at the physician who removed the ‘nevus’, and claim compensation. Therefore, complete removal and histological examination is advocated even when moles are removed for purely cosmetic reasons.