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Wednesday, June 25, 2008

What is skin cancer logoWhat are Dermal Nevi

Onset: mainly after adolescence
Site: generally appear on the face
Origin: Nests and cords of nevus cells are found within the dermis; they may extend into the subcutaneous fat
Size: vary in size from a few millimeters to a centimeter
Shape: Dome-shaped lesions are the most common, The variety of shapes reflects the evolutionary process in which moles extend downward with age and nevus cells degenerate or become replaced by fat and fibrous tissue
Appearance: elevated, fleshy, and slightly or moderately pigmented papules, may appear as a soft, flabby, wrinkled sack
Surface: smooth, may be white or translucent, with telangiectatic vessels
Color: brown or black, but may become lighter or flesh-colored with time
Border: symmetric, white borders may appear, creating a halo nevus
Special features: Pigmentation may be arranged in flecks. Coarse, dark, terminal hairs may grow from the nevus. may be warty or polypoid. Pedunculated lesions with a narrow stalk are located on the trunk, neck, axilla, and groin
Complications: prone to trauma from clothing and other stimuli, often causing them to bleed
Progress: Degeneration into melanoma is rare
Differential Diagnosis: 1- dermal nevi may resemble nodular melanoma, 2- trauma causing them to bleed and inflame, influencing some patients to suspect malignancy. 3- telangiectatic vessels on the surface mimicking basal cell carcinoma.


Histologically Dermal Nevi are composed of nests and cords of nevus cells are found within the dermis; they may extend into the subcutaneous fat. Melanocytic cells are pale, uniform in size and are found in cords or clusters surrounded by collagen bundles in the dermis.














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