Description of the procedure and treatment:

Dysplastic nevi pose a significant risk of transforming into melanoma, therefore should be removed surgically with a margin of a few millimetres and the full depth of the skin. Current treatment approaches emphasise that there are no medical grounds for prophylactic excision of lesions not suspected of being malignant, yet it is still advisable to excise the lesions disturbing for the patient.

Other acquired nevi may be removed for cosmetic indications (mainly on the face) or functional indications (irritation caused by clothing, placement in the bending areas of the body) and these are the most common reasons for the procedures performed. Since the risk of malignancy in this group is minimal (only slightly higher than in the unaffected skin), mostly the aesthetic outcome should be borne in mind during the excision.

The traditional procedure preferred by surgeons involves a spindle-shaped excision along the so-called Langer’s lines with a margin of approximately 1 mm and the full depth of the skin, followed by suturing. Such radical procedure is necessary if nevi are located in deeper layers of the skin, for example blue or hairy nevi (deep-lying hair follicles may contain melanocytes).

If the nevi are located superficially (up to the papillary layer of the dermis), instead of the full-thickness skin excision a tangential shave excision may be considered, often accompanied by electrodessication of the wound bed and with secondary healing by epithelialisation. Such a procedure facilitate obtaining aesthetically satisfying, flat scars. However, there is always the risk of incomplete removal of the nevus (persistent or recurrent pigmentation), which happens in about 10% of cases. Moreover, a recurring nevus may pose difficulties in histological differentiation with melanoma. In such cases, histological picture reveals cicatricial fibrosis in the superficial layers of the dermis, the presence of melanocytes (single or in nests, often pagetoid) and pigment in the dermal-epidermal junction layer, as well as (though not always) nests of nevus cells in the deeper layers of the dermis. The whole image may give the impression of melanoma (pseudomelanoma), but in contrast to melanoma, melanocytes in the recurring nevus aggregate over the scar area only.

In case of the nevus regrowth, some authors suggest surface re-ablation by freezing, re-shaving, or full-thickness skin excision accompanied by histological examination – information about the previous procedure must necessarily be included in the histopathological examination referral note.

Laser removal of nevi also remains a controversial matter. It is traditionally believed that the irritation of melanocytic tissue may lead to its malignant transformation, therefore laser ablation is not a commonly accepted treatment option.

However, according to guidelines which can be found in some recent reports, acquired marginal nevi may be removed by means of laser selective photothermolysis, e.g. with a ruby laser, which do not cause significant thermal damage.

Postoperative recommendations:

If there is a postoperative wound, proper wound care with suitable agents and protection against inflammation should be provided.

Important information:

Procedure duration: 30-90 minutes
Type of anaesthesia: local
Required tests and preparation: none
Contraindications: purulent infections and inflammations of the skin