Melanoma is a rather rare but deadly tumor arising from epidermal melanocytes; it can occur both on the intact skin and in the presence of a dysplastic nevus.

OBJECTIVE

To determine indications for excision of a dysplastic nevus for the prevention and early diagnosis of cutaneous melanoma.

MATERIAL AND METHODS

In 2009 to 2019, the Central Polyclinic of the Literary Fund excised 174 pigmented lesions in patients with the clinical diagnosis of a progressive dysplastic nevus.

RESULTS

Histological examination revealed 16 (9.2%) early melanomas and 133 (76.4%) dysplastic nevi; 27 (15.5%) of the 174 cases were found to have grade 3 lentiginous melanocytic dysplasia, i.e. the diagnosis of progressive dysplastic nevus was confirmed. Melanoma in situ was identified in 6 cases; invasive melanoma 0.75-1.0 mm in Breslow thickness and Clark expression levels 2-3 were observed in 10. Six (37.5%) of the 16 cases developed melanoma in the presence of dysplastic nevus, including melanoma in situ (n=4) and invasive melanoma (n=2). Large progressive dysplastic nevi with transition to melanoma (n=4) had clinical and morphological similarities with Dubreuil’s melanosis.

CONCLUSION

The signs of a progressive dysplastic nevus are an indication for its excisional biopsy. A change in a new or pre-existing nevus for 6-12 months or 1-10 years should be regarded as the main sign of a progressive dysplastic nevus in individuals after the onset of puberty. The progressive dysplastic nevus is excised, offsetting by 1 cm from the visible boundaries; this allows resurgery to be avoided, if early invasive melanoma is detected.