There are four types of melanoma – superficial spreading melanoma, lentigo maligna melanoma, acral lentiginous melanoma, and nodular melanoma. There are also several types of precancerous conditions that can develop into melanoma if they aren’t treated.
Superficial spreading melanoma
Superficial spreading melanoma is the most common type of melanoma. With this type of melanoma, the cancer cells usually stay in the top layer of skin cells called the epidermis. This is considered an in-situ phase, and it can last months, years, or even decades. The next phase is called the radial growth phase. During this phase, the cancer cells grow horizontally along the surface of the skin. The cancerous growths, often called melanoma lesions, tend to look like flat areas of discolored skin that grow slowly.
Sometimes, superficial spreading melanoma can grow deeper into the skin, and the cancerous cells enter a deeper layer of the skin called the dermis. There are also cases when another type of melanoma – nodular melanoma – grows within the superficial spreading melanoma and spreads deep within the skin.
Superficial spreading melanoma looks like a flat area of discolored skin that might look like a flat mole or a freckle. It might be months of years before it changes and becomes more recognizable as cancer. Doctors often use the ABCDEs of melanoma to decide whether a skin lesion should be biopsied. The characteristics of superficial spreading melanoma include:
- Larger than 6mm in diameter
- Irregular shape
- Variable colors of pigment within the lesion that may include different shades of brown, black, blue, grey, red, and pink
- Areas within the lesion that are skin colored or white
- A smooth, flat surface at first that can thicken and become dry or wart-like
When superficial spreading melanoma becomes more invasive, it may have the following characteristics:
- Part of the lesion may become thick
- The number of colors may increase, often including blue and black
- It may bleed or ulcerate
- It may itch or sting
Lentigo maligna melanoma
Lentigo maligna melanoma starts as lentigo maligna, also known as Hutchinson melanotic freckle. Before lentigo maligna develops into melanoma, the cancerous cells remain in the epidermis. Once the cancer cells have invaded the dermis and deeper layers of skin, it is considered lentigo maligna melanoma.
This form of melanoma usually occurs on areas commonly damaged by sun exposure, such as the face and neck. It usually first appears like freckles or brown marks on the skin, but with time, it often changes into larger, more irregular shapes. The ABCDEs of melanoma can also be used to help diagnose it. The characteristics of lentigo maligna melanoma include:
- Larger than 6 mm; it can be more than an inch in diameter when it’s diagnosed
- Irregular shape
- Variable colors, including white, tan, light and dark brown, red or pink
- A smooth surface
Acral lentiginous melanoma
Acral lentiginous melanoma grows on the palms of the hands, on the soles of the feet, or under the fingernails or toenails. It is more commonly found on the feet than in other areas of the body. It can develop from normal looking skin or a normal mole.
Acral lentiginous melanoma begins as a flat area of discolored skin that slowly gets bigger. Like most other forms of melanoma, the cancer cells stay within the epidermis at first. This in situ phase can last for months or years before it progresses to the next phase. Quick growing nodular melanoma can also grow from acral lentiginous melanoma and invade deeper areas of the skin. When acral lentiginous melanoma starts on the palm, sole, fingers or toes, it may be mistaken as a stain on the skin. It can also be characterized using the ABCDEs of melanoma.
The characteristics of acral lentiginous melanoma include:
- Larger than 6mm in diameter
- Variable colors, including a mixture of brown, blue-grey, black and red
- Starts with a smooth, flat surface and grows into a thicker, irregularly shaped lesion that can be scaly or wart-like
- It may bleed or ulcerate
Nodular melanoma
Nodular melanoma is a quick growing form of melanoma that is dangerous due to its fast rate of proliferation. Fortunately, only about 15 percent of melanomas are nodular; however, nodular melanoma accounts for almost half of all deaths related to melanoma.
Because it grows quickly and is so dangerous, it’s important to know the signs and symptoms. The earlier you find and treat it, the better your chances of being cured will be.
Nodular melanoma can look like a mole, a pimple, a bite or a lump on the skin. It may be round and black, but it can be other colors, and it may have an irregular shape. Nodular melanoma can occur anywhere on the body, but it most often shows up on the legs, arms, chest, back, sides and head.
If you see any lump or bump on your body that doesn’t go away within 5 days, have it checked by your doctor. And do not try to remove it or pop it. It won’t cause the bump to go away, and you will create a wound on your skin.
Nodular melanomas are not as easy to diagnose as other forms can be because they don’t follow the ABCDEs of melanoma. They tend to have smooth, even borders, and they’re frequently symmetrical. Most of the time, they are round, black bumps, but they can also be red, blue, grey, or white. And sometimes, though not often, they are the same color as your skin or just slightly different.
Melanoma care at Beaumont
Regardless of the type of melanoma you have, doctors at Beaumont can help. If you have any signs and symptoms of melanoma, see a doctor right away to have a skin exam. You should also talk to your doctor about your risks for developing melanoma and whether you should have professional skin exams. Beaumont dermatologists can diagnose and treat melanoma, including performing Mohs’ surgery.
Call 800-633-7377 today to schedule an appointment with a Beaumont dermatologist or to get a referral.