What is Cutaneous Melanoma?
Melanoma that occurs on the skin, called cutaneous melanoma, is the most common type of melanoma. This type of melanoma can occur in any part of the skin, including the soles of feet, on the palms of the hand, in between toes and fingers, and underneath the finger and toe nails. If you have cutaneous melanoma it is important to know your diagnosis and treatment options. We have provided resources for people diagnosed with cutaneous melanoma.
Types of Cutaneous Melanoma
Superficial Spreading Melanoma
Superficial Spreading Melanoma (SSM) accounts for approximately 70% of all diagnosed melanomas. It usually occurs in a previously benign (non-cancerous) mole and is most commonly found on the trunk and back in men and on the legs and back in women. In early stages, SSM may look like a freckle that is spreading sideways on the skin. Over time, the color could darken or lighten, the area may itch, or the lesion could grow or develop irregular borders. SSM can progress rapidly, so if you see a lesion or mole that you suspect could be melanoma, have it checked out by a dermatologist immediately.
Nodular melanoma accounts for approximately 15% of all diagnosed melanomas. It may appear where a mole or lesion did not exist before. It tends to spread more rapidly in depth and is almost always considered invasive (deep) at the time of diagnosis. Nodular melanoma is the most aggressive type of cutaneous melanoma, is more common in males and can occur at any age but is most often seen in individuals aged 60 and older.
Acral Lentiginous Melanoma (ALM)
Although acral lentiginous melanoma only accounts for about 5% of all diagnosed melanomas, it makes up about 50% of diagnosed melanomas in Asians and in individuals with dark skin. These melanomas can develop anywhere on the body, including the palms of the hands, the soles of the feet or underneath the fingernails and toenails. On the palm or sole of the foot, ALM can look like a bruise or an irregular tan, brown or black spot.
Subungual melanoma is a rare sub-type of ALM. Most subungual melanomas involve the thumb nail or the nail of the great toe. If you have a dark spot under your fingernail or toenail that appears, be sure to bring it to the attention of your dermatologist – especially if there has not been any recent trauma to the area (sometimes a bruise caused by trauma to the fingernail or toenail can look similar to a melanoma).
Reggae musician Bob Marley died in 1981 of complications from acral lentiginous melanoma, which originated under his toenail and metastasized to other parts of his body.
Lentigo Maligna Melanoma
Lentigo Maligna Melanoma (LMM) accounts for approximately 10% of all diagnosed melanomas. It often occurs on the face of middle-aged to elderly individuals who have experienced sun damage. It can be mistaken as “sun spots” and go undetected, making it very dangerous. As these lesions spread in width and in depth they will typically have a very irregular border and vary in shades of brown or black. Sometimes dark nodules will appear within the brown or black area and will feel like small bumps.
Desmoplastic melanoma (DM) is a rare subtype of cutaneous melanoma in which the melanoma cells are surrounded by fibrous tissue. DM most commonly develops on the sun-exposed areas of the head and neck. The majority of people diagnosed with DM are older-age males with chronic UV exposure and sun-damaged skin. About half of DMs develop in association with a lentigo maligna melanoma. They are often difficult to diagnose and, therefore, tend to be quite invasive (deep) at the time of diagnosis. Although DM is associated with a higher tendency for local recurrence, regional lymph node involvement is less common.
Genetic Mutations in Melanoma
Knowing your mutation status is critical for laying out your treatment options. Several genetic mutations are found in melanoma that ‘drive” the disease. A class of drugs called targeted therapies were designed to specifically target these mutations.Webinar: Why Test for BRAF?
- BRAF – The BRAF mutation is the most common type of genetic mutation in cutaneous melanoma (melanoma of the skin), appearing in approximately 50% of cases.
- NRAS – The NRAS mutation is less common than the BRAF mutation but occurs in approximately 20% of cutaneous melanoma cases.
- KIT – The KIT mutation is the most common mutation in mucosal melanoma. This mutation is also common in acral melanoma.
- GNAQ and GNA11 – The GNAQ and GNA11 mutations are the most common mutations in ocular melanoma (melanoma of the eye).
Experts recommend that patients with high-risk Stage II and all Stage III and Stage IV melanoma patients have their melanoma tested for genetic mutations so the proper treatment options can be discussed.