There are several different types of melanoma. For most types, the cancer begins in the top layers of the skin—referred to as “in situ”—but melanoma can become invasive by growing deeper into the skin and spreading to other areas of the body. Other types are considered invasive from the start. In men, it is most common for melanoma to develop on the back. In women, melanoma most often occurs on the legs. It’s important to note, however, that melanoma can develop on any area of the body—even unsuspecting places such as on genitalia, under the fingernails or on the soles of the feet.
Melanoma typically falls into one of three general categories:
- Cutaneous melanoma – melanoma of the skin
- Mucosal melanoma – melanoma of any mucous membrane, such as the throat, mouth, vagina or anus
- Ocular melanoma – melanoma occurring in the eye
Cutaneous melanoma is the most common of these categories, and the four main types of cutaneous melanoma include:
Superficial spreading melanoma
The majority of cutaneous melanoma cases (approximately 70%) fall under this type. The cancer usually develops in an ordinary mole that previously was benign (not cancerous), and it often remains "in situ" quite a while before penetrating deeper. The melanoma may appear as a flat or slightly raised patch of the skin that is discolored, has irregular borders and is asymmetrical. The color may include areas of brown, red, white, blue, black or tan.
This is the most aggressive form of cutaneous melanoma. Nodular melanoma typically appears as a dark bump—usually black, but lesions may also appear as colorless skin tones. Because it doesn’t look like the usual atypical mole, it can escape notice. Nodular melanoma may develop where a mole did not previously exist. Most commonly, it develops on areas exposed to the sun, such as the face, back, legs, arms and chest.
Lentigo maligna melanoma
Lentigo maligna melanoma tends to grow on the surface of the skin for a while before becoming invasive. It most often appears as a flat or slightly raised mottled discoloration of brown or tan. This melanoma is most common in elderly individuals who have experienced extensive sun exposure, and can sometimes be mistaken for sunspots.
Acral lentiginous melanoma
A more rare form of melanoma, acral lentiginous melanoma begins “in situ” and is found most frequently in African-Americans and Asians. It can appear on the soles of the feet or palms of the hands resembling a bruise or colored patch. It may also occur under the fingernails or toenails, looking like a dark streak or discoloration.
Mucosal melanoma is a very rare form of melanoma, accounting for only 1% of cases. It develops on mucous membranes, which are moist surfaces lining major cavities in the body. There are a handful of subtypes of mucosal melanoma, which are named based on the area of the body where they are found:
- Oral mucosal melanoma
- Vulvar mucosal melanoma
- Anorectal mucosal melanoma
- Mucosal melanoma of the head and neck
- Vaginal mucosal melanoma
Researchers are still investigating the cause of mucosal melanoma, as it is not related to sun exposure like most cutaneous melanoma subtypes are. Some risk factors have been identified—such as a genetic link with DNA mutations of the KIT gene—but none have been widely accepted by the science community.
The most common primary cancer of the eye in adults, ocular melanoma accounts for 5% of all melanoma cases. It is an aggressive form of cancer that can affect the uvea, which includes the iris, the ciliary body (an extension of the iris that produces fluid in the eye) and the choroid (the vascular layer of the eye, between the retina and sclera). Diagnosing ocular melanoma can be difficult, as it grows in an area that isn’t visible and doesn’t often produce symptoms. Those who do experience symptoms of ocular melanoma may have:
- Blurry vision in one eye
- A change to the shape of the pupil
- A dark spot on the iris that grows in size
- A sensation of flashes or specks of dust in their vision
- Unexplained loss of peripheral vision
While there is no known cause of ocular melanoma, it is common among people with lighter skin and blue eyes.
What is metastatic melanoma?
Metastatic melanoma occurs when cutaneous melanoma spreads from the skin to other areas of the body. Most commonly, metastatic melanoma spreads to the lymph nodes, lungs, liver, bones, digestive system or brain. When this happens, the cancer is considered to be stage 4 melanoma and can result in such symptoms as:
- Appetite changes
- Unexplained weight loss
- Swollen lymph nodes
- A persistent cough
While each patient with metastatic melanoma will undergo their own individualized treatment plan, most patients require surgery as well as one or more of the following options: chemotherapy, radiation therapy, immunotherapy and limb infusion and perfusion.
Melanoma treatment at Moffitt Cancer Center
Moffitt Cancer Center offers diagnosis of and treatment for melanoma in a single location. Our Cutaneous Oncology Program features an expert team of melanoma specialists—from surgical oncologists to plastic surgeons, dermatologists and pathologists—who work together to develop individualized treatment plans for our patients. What’s more, all of our specialists are involved in ongoing research to develop new skin cancer treatments and learn more about genetic risk factors to better help our patients.
Moffitt is the only National Cancer Institute-designated Comprehensive Cancer Center based in Florida, an accolade we’ve earned because of our commitment to cancer research. For example, we offer a robust clinical trials program, allowing our patients to be the first to benefit from novel treatments.
All types of melanoma require immediate attention, as they are more successfully treated when caught in their early stages. If you suspect you may have a form of skin cancer, call 1-888-663-3488 or complete our new patient registration form online. We provide every new patient with rapid access to a cancer expert within a day—faster than any other cancer hospital in the nation.