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(mole, birthmark), a congenital malformation of the skin in which some areas differ in color from the rest of the skin and/or have a peculiar warty appearance. Nevi are not confined to any particular area. They can be present at birth or develop during the first few years of life or even later.
Vascular nevi, or hemangiomas, are characterized by varying sizes, uneven edges, and a pink or bluish red color. They become pale when pressed and may be flat, superficial (capillary nevi), or nodular. They are embedded in the thickest part of the skin and have an uneven cavernous surface (cavernous nevi). Verrucoid nevi occur as singular or multiple patches of different shapes, are muddy gray or brown in color, and have an uneven keratotic surface. Pigmented nevi are light brown to almost black in color; they can be the size of a pinhead, or they can cover large areas of the skin. The surfaces of pigmented nevi may be uneven and covered with hair (Becker’s nevi).
Self-treatment of pigmented spots is dangerous because frequent injury may cause them to degenerate into melanomas, whereupon the nevi enlarge, become firmer, and change color. New pigmented spots may appear in the same area, and the regional lymph nodes may become enlarged.
Electrocoagulation, cryotherapy, surgical dissection, and radiotherapy are used to treat nevi.
REFERENCEShanin, A. P. “Nevusy.” In Mnogotomnoe rukovodstvo po dermatologii, vol. 3. Moscow, 1964.
I. IA. SHAKHTMEISTER