*1. unctional (active) nevus *2. Intradermal (resting) nevus *3. Dysplastic nevus syndrome
4.Lentigines. These are to be differentiated from freckles (ephelides). A freckle histologically shows hyperpigmentation of the basal layer but no elongation of the rete pegs and no increase in the number of clear cells and dendritic cells. Juvenile lentigines (lentigo simplex) begin to appear in childhood and occur on all parts of the body. Senile lentigines (see Fig 34-2), also known as "liver spots," occur in elderly persons on the dorsa of the hands, the forearms, and the face. Solar ink-spot lentigo is commonly seen on sun-exposed areas and has a characteristic black, splotchy, reticulated pattern. Lentigo maligna melanoma (see Fig.SS-B) is a dark brown or black macular, malignant lesion, usually on the face or arms of elderly persons, that has a slow peripheral growth (see under Malignant Melanoma earlier). Lentigines can be caused by ionizing radiation, a tanning bed, a sunlamp, PUVA therapy, and, most commonly, from sun exposure.
5.Mongolian spots (see Fig 33:8). These are seen chiefly in Asian or African-American infants, usually around the buttocks.
Related bluish patchy lesions are the nevus of Ota, seen on the side of the face, and the nevus of Ito, located in the supraclavicular, scapular, and deltoid regions. Laser therapy may be beneficial.
6.Blue nevus. Clinically, the blue nevus appears as a slate blue or bluish black, sharply circumscribed, flat or slightly elevated nodule, occurring on any area of the body. It originates from mesodermal cells.
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Complete Guide to Preventing Skin Cancer. We all know enough to fear the name, just as we do the words tumor and malignant. But apart from that, most of us know very little at all about cancer, especially skin cancer in itself. If I were to ask you to tell me about skin cancer right now, what would you say? Apart from the fact that its a cancer on the skin, that is.