Young Blonde Girl With Long Hair And White Heels Shows Off Her Body Nevus Behind The Pink Curtain

Nevus (or naevus, plural nevi or naevi, from nævus, Latin for "birthmark") is the medical term for sharply circumscribed and chronic lesions of the skin. These lesions are commonly named birthmarks or beauty marks. Nevi are benign by definition. However, 50% of malignant melanomas (a skin cancer) arise from pre-existing nevi. Using the term nevus and nevi loosely, most physicians and dermatologists are actually referring to a variant of nevus called the "melanocytic nevus", which are composed of melanocytes. Histologically, melanocytic nevi are differentiated from lentigines (also a type of benign pigmented macule) by the presence of nests of melanocytes, which lentigines (plural form of lentigo) lack.