Moles, brown spots and growths on the skin are usually harmless-but not always. Melanoma, the most dangerous form of skin cancer, originates in the pigment-producing melanocytes in the basal layer of the epidermis. Melanomas often resemble moles; some can develop from moles. The majority of melanomas are black or brown, but they can also be skin-colored, pink, red, purple, blue or white. Melanoma is caused mainly by intense, occasional UV exposure (frequently leading to sunburn), especially in those who are genetically predisposed to the disease. If melanoma is recognized and treated early, it is almost always curable.
BASAL CELL CARCINOMA (BCC):
The most frequently occurring form of skin cancer, BCCs are abnormal, uncontrolled growths or lesions that arise in the skin’s basal cells, which line the deepest layer of the epidermis (the outermost layer of the skin). BCCs often look like open sores, red patches, pink growths, shiny bumps, or scars and are usually caused by a combination of cumulative and intense, occasional sun exposure. Though BCC almost never spreads (metastasizes) beyond the original tumor site, this condition shouldn’t be taken lightly; it can be disfiguring if not treated promptly.
SQUAMOUS CELL CARCINOMA (SCC):
The second most common form of skin cancer, SCCs are uncontrolled growths of abnormal cells arising in the squamous cells, which compose most of the skin’s upper layers (the epidermis). SCCs often look like scaly red patches, open sores, elevated growths with a central depression, or warts; they may crust or bleed. SCCs may occur on all areas of the body including the mucous membranes and genitals, but are most common in areas frequently exposed to the sun, such as the rim of the ear, lower lip, face, balding scalp, neck, hands, arms and legs. They can become disfiguring and sometimes deadly if allowed to grow.
ACTINIC KERATOSIS (AKs):
A potential precancer also called solar keratoses, actinic keratoses scaly, crusty growths cause by damage from the sun’s ultraviolet (UV) rays. They typically appear on sun exposed areas and are often elevated, rough in texture, and resemble warts. Most become red, but some will be tan, pink, and/or flesh-toned. If left untreated, up to ten percent of AKs develop into SCCs, and in rarer instances may also turn into BCCs.
(all info from www.skincancer.org)