GROWTH AND MOLE
Non-dermatologists refer to any pigmented skin spot or growth as a mole. Dermatologist call any cluster of pigment cells, whether raised or flat, pigmented or skin-colored a mole or a nevus. Pigment cells, the so-called melanocytes, reside normally at the base of the superficial layer of the skin, the epidermis. They are shaped like an octopus, spitting out pigment particles, i.e., melanin, which the neighboring keratinocytes engulf, and house them like a cap on top of their nuclei. Benign clusters of the melanocytes, i.e., nevi (the plural of nevus), can populate the border of he epidermis and the dermis, or be present within the dermis. Benign thickening of he outer layer of the skin, the keratinocytes, are commonly noted stuck-on growths that have a rough warty brain-surface appearance. Non dermatologists call them moles, but the dermatologists call them seborrheic keratosis. Seborrheic keratoses behave very differently than nevi, and can be removed somewhat differently. Seborrheic keratoses become itchy commonly, whereas, nevi become itchy rarely.
Nevi can be unicolored, or be two-toned and, in addition, have irregular borders. Two-toned nevi with irregular borders should be screened regularly, and people who have them on their skin should be screened by a dermatologist at least once a year.
HOW DO MOLES DEVELOP?
The development of seborrheic keratoses and nevi are genetically determined. Environmental factors, such as ultraviolet light exposure, sunburns of the past, exposure to air pollutants, and traumatic events such as repeated excessive heat exposure or friction of a rough loofa can contribute to the development of them in genetically predisposed people.
Nevi can be present at birth or early childhood, but seborrheic keratoses develop after the second decade. The nevi that are present in early childhood behave biologically differently than nevi that are acquired from teenage years onward.
nevi in all cases.