Dysplastic nevus is widely debated, it ’s defined like an acquired mole, often large with specific histological characteristics. Dysplastic moles are generally larger than ordinary moles and have irregular and indistinct borders, their color frequently ranges from pink to dark brown; they are flat and sometimes parts may be raised above the skin surface. They are most common on the trunk, abdomen and arms. Histologically the he melanocites are increased, often the teches appears irregular in shape and they can be extended deep inside the skin. The papillary derma is fibrous and there is a lymphocitic infiltrate, usually we can find increase vascolarization and rare cytologic atypias. The displastic moles have an high incidence in the general population.
The dysplastic nevus syndrome is autosomal dominant with high penetrance and variable expressivity; a chromosome instability disorder was observed in cell cultures from the normal skin and dysplastic nevi over three-generations in DNS families, leading to translocations, duplications and deletions (see https://atlasgeneticsoncology.org/Kprones/DysplNevusID10013.html). In these patients we can find more than 100 dysplastic moles and their risk to have a melanoma is doubled then general population. It is extremely important the follow up and the excision of the changing moles