What is Melanoma?
Melanoma is the most serious type of skin cancer, and the fifth most common cancer in men and seventh most common cancer in women. In the United States, the rate of melanoma is rising more rapidly than any other potentially preventable cancer.
There are four subtypes of melanoma: superficial spreading, nodular, lentigo maligna, and acral lentiginous.
Superficial spreading melanoma is the most common subtype of melanoma. Superficial spreading melanoma can occur in any area, but arises more commonly on the lower legs in women and on the back in men.
Nodular melanoma is the second most common subtype. Nodular melanoma is the hardest to diagnose at an early stage.
The lentigo maligna melanoma subtype occurs most commonly in sun-damaged skin in the older population. Lentigo maligna lesions start as beige/brownish patches that later get larger and form darker, uneven areas with differences in color. Lentigo maligna lesions also develop elevated areas, which indicate that the lesion is growing vertically.
Acral lentiginous melanoma is the most common subtype of melanoma in people with darker skin. Acral lentiginous melanoma usually occurs on the palms of the hands and soles of the feet, as well as under the nails. When in the nail, acral lentiginous melanoma appears as a black or brown band.
What does melanoma look like?
The appearance of melanoma varies dramatically, so it is nearly impossible to describe exactly what melanoma looks like. However, there are some important early traits of melanoma to be aware of. These are best remembered using the acronym “ABCDE:”
Asymmetry: an imaginary line down the center of the lesion is a good indicator of symmetry, and melanoma is often asymmetrical.
Border irregularity: Melanoma often does not have a consistent, even border.
Color differences within the lesion: Colors in melanoma can range from black, brown, red, blue, gray, and white. Note the range of colors in the same lesion depicted below.
Diameter: Melanoma diameter is often larger than 6 mm
Evolution: Melanoma lesions often exhibit changes in size, color, or shape.
What are the risk factors for developing melanoma?
The most important factor for developing melanoma is sun exposure. People who have had more sun exposure, including tanning beds, are at increased risk. Other risk factors include having atypical nevi (moles), a large number of atypical nevi, and having blond or red hair, many freckles, or light eye color. A small percentage of patients with melanoma have a genetic predisposition that puts them at increased risk.
The most important factor that decides the prognosis is the tumor thickness. Survival rates decline as tumor thickness increases. Regular skin exams by a licensed dermatologist are important in maintaining skin health and can allow early detection of melanoma.