What are Nevi, or Moles, part two

Junction nevi.
Junction nevi are flat (macular) or slightly elevated, and they are light brown to brown-black with uniform pigmentation that may be slightly irregular . The surface is smooth and flat to slightly elevated, and the border is round or oval and symmetric. Most lesions are hairless. Junction nevi vary in size from 0.1 to 0.6 cm; some are larger. Junction nevi may change into compound nevi after childhood, but they remain as junction nevi on palms, soles, and genitalia. Junction nevi are rare at birth and generally develop after the age of 2 years. Degeneration into melanoma is very rare.
Compound nevi.
Compound nevi are slightly elevated and flesh colored or brown. They are elevated and smooth or warty and become more elevated with increasing age . They are uniformly round, oval, and symmetric. Hair may be present. If a white halo appears at the periphery of the lesion, it is referred to as a halo nevus.
Dermal nevi.
Dermal nevi are brown or black, but may become lighter or flesh-colored with age. Lesions vary in size from a few millimeters to a centimeter. The variety of shapes reflects the evolutionary process in which moles extend downward with age and nevus cells degenerate and become replaced by fat and fibrous tissue.
Dome-shaped lesions are the most common . They generally appear on the face and are symmetric, with a smooth surface. They may be white or translucent, with telangiectatic vessels on the surface mimicking basal cell carcinoma. The structure may be warty or polypoid . Pedunculated lesions with a narrow stalk are located on the trunk, neck, axilla, and groin. They may appear as a soft, flabby, wrinkled sack.
Elevated nevi are exposed and are prone to trauma from clothing and other stimuli, often causing them to bleed and inflame, influencing some patients to suspect malignancy. White borders may appear, creating a halo nevus. Degeneration to melanoma is very rare, but dermal nevi may resemble nodular melanoma; therefore, knowledge of duration is important.

Management of common moles
Suspicious lesions.
Any pigmented lesion suspected of being malignant should be biopsied or referred for a second opinion. Suspicious lesions should be completely removed by excisional biopsy down to and including subcutaneous tissue.
Nevi.
Patients frequently request removal of nevi for cosmetic purposes. It is good practice to biopsy all pigmented lesions; therefore, total removal by electrocautery should be avoided. Nevi are removed either by shave excision or by simple excision and closure with sutures. Most common nevi are small and consequently shave excision is adequate.
Recurrent previously excised nevi (pseudomelanoma).
Weeks to months after incomplete removal of a nevus, brown macular pigmentation may appear in the scar. Some nevus cells remain with shave excision and partial repigmentation is possible. Residual pigmentation may be removed with electrocautery or cryosurgery. An unusual histologic picture resembling melanoma (pseudomelanoma) may follow partial removal of nevi. If the repigmented area is excised, the pathologist should always be notified that the submitted tissue was acquired from a previously treated area. Histologically, the melanocytes appear atypical but are confined to the epidermis, and there is no lateral spread of individual melanocytes.
Nevi with small dark spots.
A small percentage of small dark dots within melanocytic nevi is due to melanoma. These roundish areas of brown or black hyperpigmentation measure 3 mm or less in diameter and are located peripherally. Biopsy specimens of nevi with small dark dots should be sectioned to ensure histologic examination of this focus of hyperpigmentation.