Only a small number of babies have skin growths at birth. By the time we are 80-90 years of age, it is normal to have numerous benign skin growths. Benign skin growths usually appear rather suddenly over days or weeks and then stay the same. These stable lesions are often readily identifiable, asymptomatic and require no treatment. Skin cancer will continuously change and progressively increase in size.
Skin cancer is more often irregular in appearance and shape and may be painful or inflamed. Occasionally, benign skin lesions may be confused with skin cancer. A small biopsy may be necessary to distinguish benign from malignant. Benign skin lesions can also be removed if they itch or are painful when rubbed or irritated. Removal or treatment of benign skin lesions may also be cosmetically desired.
Moles are called nevi by the medical profession. By age 30, the average person has about 30 nevi. After about 30 years of age, the number of nevi is relatively stable. These are benign growths of neural origin. Under the microscope, these cells share features with nerve cells and brain cells. The number of moles is partially genetically determined and partially related to sun exposure in childhood. The more sun exposure in early childhood, the larger the number of moles. Benign moles are uniform in color and shape and do not change darker and larger. Any “mole” that is growing larger, darker and more irregular is concerning for melanoma – the cancerous form of “mole.”
The skin growths commonly called “barnacles” are named seborrheic keratoses by the medical profession. Seborrheic keratosis is Greek for “oily scale.” These warty growths appear to be stuck on the skin and are discrete and scaly. They come in many sizes from small to large and vary in color from white to skin colored to brown to black. The cells are related to the top layer of skin or epidermis. The number of seborrheic keratoses are inherited and unrelated to sunlight. Almost everyone over 60 years old has at least a few of these with the first seborrheic keratosis appearing after 30 years of age. In contrast to skin cancer, these growths appear suddenly and are then stable. Pigmented seborrheic keratoses are often scaly and thick in contrast to changing, flat, non-scaly melanoma. Seborrheic keratosis are easily removed for diagnosis or treated with liquid nitrogen for symptoms of irritation or cosmetic reasons.
“Liver spots” or lentigos are tan to brown spots produced by sunlight. The term “liver” applies to the color of these spots. There is no relationship to a liver diagnosis. The cells of lentigos are related to melanocytes, the pigment producing cells within the top layer of skin. In contrast to freckles, these spots persist and are stable. Lentigos may be somewhat irregular but are usually uniform in color. Like all benign lesions, they appear suddenly then do not change shape, color or size. Prevention of lentigos is difficult in Arizona and requires life-long sun protection or avoidance. Multiple lentigos may be a sign of previous sunburn, often years ago. Lentigos are usually asymptomatic and do not have to be treated. Cosmetic improvement may be seen with bleaching or blending creams, intense pulse light, laser or liquid nitrogen treatments.
Pictures of these common benign growths can be found on the Internet by searching “benign nevus pictures,” “seborrheic keratosis pictures” or “lentigo pictures.”
By Carl Bigler, M.D.
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