An Seborrheic Keratosis variant, with earlier onset than the ordinary form. It affects the upper cheeks and lateral orbits of dark-skinned individuals, with small, multiple, pedunculated, and heavily pigmented lesions.
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Lesions are round to oval, pigmented, initially flat, but subsequently raised and with a velvety to finely
verrucous surface. Margins are sharp (as if stuck on normal skin) and have a soft and greasy look. Usually <1 cm at onset, they grow thicker and larger with time, while new lesions continue to appear. Often aligned in the direction of skin folds, they can have keratotic plugging on the surface. Although more common in sun-exposed areas (and often arising from solar lentigines), they may occur anywhere, except for the palms, soles, and mucous membranes. The most common benign tumors of old age, present in as many as 90% of people older than 65 and increasing in number with age. They have a variety of appearances and pigmentation and are due to
proliferation of epidermal cells. Although entirely benign, they can be cosmetically unappealing and often provide a daily reminder of the annoying effects of aging. In fact, they are often referred to as benign senile verrucae, or senile warts. They also can grow, itch, become irritated, and even infected, especially from scratching or other mechanical irritation. It is the familial atypical multiple mole and melanoma (FAMMM) syndrome (also known as dysplastic nevus
syndrome), in which family members develop >100 melanocytic nevi, which is far more than the average number of common nevi (15–20). Lifetime risk for melanoma is high. In fact, close to 100% for individuals with >100 lesions and more than two family members with melanoma history. They are larger than common moles (5–15 mm in diameter) and often variegated (tan to dark brown to
pink). They occur in both sun-exposed and sun protected areas, more commonly the back, chest, buttocks, breasts, and scalp. Since they grow through lateral extension, they often assume the configuration of a fried egg, with a central papule and a surrounding macular area of differing pigmentation. Due to their lateral extension, they have notched and poorly defined rims. They are acquired variants typical of families of northern European descent, with fair skin, light-colored
hair, freckles, and other Celtic features. The United Kingdom, Netherlands, Germany, and occasionally Poland and Russia are the most affected countries. Patients present with hundreds of relatively broad lesions that are flat or thinly papular. The more numerous the nevi, the greater the likelihood of melanoma . Still, dysplastic nevi are just a marker for risk, and not necessarily a precursor. Hence, removal of all dysplastic nevi may not really alter the risk. The most important is stability—in size, height, color, and outline. Also, lack of symptoms (i.e., not itchy,
painful, irritated, or bleeding), even color (usually tan to brown), and small size (<1 cm). Melanocytic nevi are classified according to histology:
Junctional nevus: Usually a macule or thinly raised papule with well-circumscribed borders and homogeneous brown to black pigment. Cells are located in the dermoepidermal junction. Compound nevus: A raised papule, brown or tan and often lighter than a junctional nevus. Pigmentation and border are even, and cells are at the dermoepidermal junction/upper dermis. (Intra-) Dermal nevus: Also a papule, usually domeshaped, pedunculated or warty-surfaced. Cells are in the dermis. Color is brown or even flesh-like, since melanin is often lacking. They are nevi that are present at birth or soon thereafter. They are probably hamartomas, since they
contain many skin elements, but a predominance of melanocytes. Large congenital nevi have a low (5%) but real risk for malignant transformation into melanoma. Hence, the need for prophylactic excision. In a rare autosomal dominant condition, family members acquire with time many large nevi, sometimes more than 100. Benign neoplasms composed almost exclusively of melanocytes. These are so common to be considered a
normal part of the skin, such as cherry angiomata or seborrheic keratoses. They typically form during early childhood, usually in response to sun exposure. In fact, early use of broad-spectrum sunscreens can effectively reduce their development. Nevi often appear after blistering events, such as sunburns or second-degree thermal burns, suggesting once again their actinic etiology. Incidence of acquired melanocytic nevi increases in number throughout childhood and early adulthood, peaking during the fourth to fifth decade of life, with significant reduction in later years. In fact, acquired melanocytic nevi have been said to be absent at birth and at death, reflecting their slow involution with age. |