Let's Talk About the Types of Melanoma
What it looks like, where it started, whether it's spread: all factors in your specific melanoma. The need-to-knows, here.by Krista Bennett DeMaio Health Writer
Whoever said not to sweat the small stuff clearly never had a funny-looking mole. Learning that a tiny speck on your body is cancerous can sure be nerve-racking—and you certainly don’t have to be a sun worshipper to be diagnosed with a melanoma. Another misconception: that there’s just one type. We’re here to help you understand the kind of melanoma you have, provide doctor-vetted answers to your questions—and hopefully soothe some of your worries.
Our Pro Panel
We went to some of the nation’s top experts in melanoma to bring you the most up-to-date information possible.
Zeila Correa, M.D., Ph.D.
Professor of Ophthalmology and Ocular Oncologist
Johns Hopkins Medical Center
Sancy Leachman, M.D.
Chair of the Department of Dermatology at Oregon Health & Science University and Director of Melanoma Research Program at Knight Cancer Institute
Philip Friedlander, M.D.
Assistant Professor of Hematology and Oncology
Mount Sinai School of Medicine
New York, NY
For most melanomas, the treatment is determined by your stage. But in some cases, the type does dictate the course of treatment. For example, treatment for ocular melanoma may include surgery, radiation, lasers, or photodynamic therapy (low level laser and a light-activated medication). Lasers aren’t typically used to treat most skin melanomas. Melanomas on the scalp, head, and neck may be treated more aggressively because there are more blood vessels and lymph nodes in these areas, which means it can spread quickly.
Any type of melanoma can have a mutated gene in the tumor’s DNA (such as the BRAF mutation, found in about half of all melanomas). If this is present, a different course of treatment—targeted therapy—may be used. Drugs zero in on these specific mutations to fight the cancer. Some experts say as we learn more about melanoma gene mutations, tumors will one day be defined by genetics rather than type.
The stage of your melanoma tells a physician a few important things: how early or advanced the disease, how at risk your tumor is for spreading, how to treat your melanoma, and your overall outlook or prognosis.
Melanomas can be super tiny, but most are larger than 6 millimeters (about ¼ inch). However, they’re staged based on their thickness, not their width. Typically, the thinner the melanoma, the better the outcome. Thicker melanomas have a greater chance of spreading. But sometimes a thinner melanoma may have spread to nearby sites or lymph nodes, making it more dangerous than a thicker melanoma that’s only within the layers of the skin.
What Exactly Is Melanoma?
One of three main types of skin cancer (basal cell carcinoma and squamous cell carcinoma are the other two), melanoma occurs when cancer strikes your melanocytes—the pigment-producing cells in your skin that give your skin pigment when you freckle or tan. When these cells turn cancerous, you might see a mole that’s large, uneven, or somehow doesn’t look like your others.
While fair-skinned folk are most prone, people with darker skin get melanomas too, and are often diagnosed later. Melanoma is less prevalent than its sister skin cancers, but spreads faster to other organs. Deep breath thought: When you catch it early enough, it’s almost always curable.
Unfortunately, about 5% of melanomas are particularly stealth and often diagnosed at a later stage. That’s because they don’t resemble the tell-tale brown or black mole that we associate with the cancer. Amelanotic melanomas lack pigment and can be clear, flesh-tone, or pinkish in color. They’re sneaky!
What Are The Main Types of Melanoma?
There are generally four primary types of melanoma, all of which start in the skin and are fittingly known as cutaneous melanoma. Let’s have a look:
Superficial Spreading Melanoma
What it is: Superficial spreading melanoma is pretty much what it sounds like. It starts on the surface of your skin (that’s the superficial part) and spreads out before it grows down into deeper layers of your skin. It’s the most common form of melanoma, comprising 70 percent of all cases. When caught early, it’s highly treatable. The overall five-year survival rate for superficial spreading melanoma is 95 percent, according to a study in Melanoma Research that looked at nearly 100,000 patients.
Where you’ll find it: This type pops up on areas that you often get sunburned: upper back, torso, and legs. It may be a new spot, or it may show up in an existing mole.
What it looks like: It tends to be larger than your other moles and with an irregular shape. It may start off flat, but then take on a texture over time. It can be brown or black, but also have some variations of shades such as pink, gray, even blue.
What it is: This is the most aggressive type of melanoma, so stealth that it often grows deeply into the lowest layers of skin by the time it’s diagnosed. Nodular melanoma is more common in men. It accounts for only 10 to 15 percent of all melanomas, but causes nearly half of all melanoma deaths. Even thin nodular melanoma tumors had a worse prognosis compared to superficial spreading melanomas, according to a study in the Journal of the National Cancer Institute.
Where you’ll find it: A nodular melanoma can grow anywhere on the body, but they’re more commonly found in (you guessed it) sun-exposed areas: legs, torso, arms, and the tops of heads.
What it looks like: Typically like a black bump or pimple, with even borders (not the irregular ones we’re usually told to look out for). While it might be suspiciously crusty in texture, it can also be deceptively smooth. It’s often black or bluish in color, but can also be pink or red.
Lentigo Maligna and Lentigo Maligna Melanoma
What it is: While lentigo maligna is a very early stage of melanoma that sits on the surface of skin, lentigo maligna melanoma is slow moving yet invasive, spreading into deeper layers. Elderly people are more vulnerable. It’s unlikely that a lentigo maligna will morph into a lentigo maligna melanoma over time, but also not impossible. The estimated risk of progression was just three and half percent per year, and based on the patients studied, it took 28.3 years for lentigo maligna to progress into lentigo maligna melanoma, according to a 2019 study in Melanoma Research.
Where you’ll find it: Highly sun-damaged areas, most commonly your face.
What it looks like: It starts off looking like a patch of brown, a flat freckle, or a sun spot, but then grows in size (around 6 mm) and changes in pigment.
Acral Lentiginous Melanoma (ALM)
What it is: ALM, which represents less than five percent of melanomas, is thought to have less to do with UV exposure because of where the spots appear—on hands and feet. It’s more common in those with dark skin. The survival rate is lower for Black people than for Caucasians—66 percent compared with 90 percent, respectively, according to research published in Preventing Chronic Disease, in part because it tends to be diagnosed later in this group.
Where you’ll find it: It shows up on your extremities, often in areas that don’t get a lot of sun such as the palms of your hands, the soles of your feet, and inside and around your nails and toenails.
What it looks like: ALM usually appears as a dark spot. It may be unevenly pigmented with a very sharp border. Inside the nail, it can look like a dark streak.
What Are the Less Common Types of Melanoma?
Several rarer forms of the cancer also start in your skin. Some are particularly stealth, because they don’t resemble the tell-tale brown or black mole that we associate with the cancer.
Amelanotic melanoma: Amelanotic melanomas lack pigment and can be clear, flesh-toned, or pinkish in color, and because of this, they tend to be diagnosed at a later stage. Approximately five percent of melanomas are amelanotic.
Nevoid melanoma: A nevoid melanoma confuses patients and doctors alike because it looks similar to a benign mole, except it’s not. It can be any color and is dome-shaped.
Spitzoid melanoma: Quite the chameleon, this one resembles a harmless mole (a Spitz nevus), is round and even in color, and often amelanotic (lacking pigment). It tends to show up on the head and extremities.
Desmoplastic melanoma: This type accounts for only one to four percent of all melanomas. It often looks more like a scar than a mole, with a pink or red color. It can pop up on sun-exposed areas, but most often the head and neck.
We think of melanoma as a skin cancer for good reason —that’s usually where it likes to grow. But the truth is, melanoma can happen anywhere you have melanocytes. Know that there are some rarer forms that don’t start in the skin:
Intraocular melanoma: This kind forms on the lining of the eyes (conjunctiva melanoma) and inside the eye (uveal melanoma). Metastatic skin melanoma can also spread into the eye, although that’s the rarest of all eye melanomas. Uveal melanoma can affect three different areas: the iris, ciliary body (just behind the iris) and the choroid (the eye’s vascular layer). Choroidal melanoma is the most common primary type of ocular melanomas. Like skin melanomas, ocular melanomas are triggered by UV light — so wear sunglasses! Eye melanoma is particularly dangerous because when not detected early, because it spreads easily into the bloodstream and almost always metastasizes to the liver first.
Subungual melanoma: This subtype of ALM starts under the nail, not on the surrounding skin. It can look like a dark streak or even a bruised nail. Like ALM, it’s not caused by sun exposure, and seems to be more common in dark-skinned males. You might remember that singer Bob Marley died from melanoma under the toenail.
Mucosal melanoma: This rare type of melanoma grows on the mucus linings. That can mean inside your mouth, inside and around your genitals, nasal passages, GI tract lining, and anus. Because mucosal melanoma shows up where the sun never shines, it’s particularly tricky to detect. Experts aren’t sure what brings it on; there’s no clear link to UV exposure, family history, or other risk factors. Your symptoms may include bleeding, a noticeable mass, pain, or in the case of the genitals, abnormal discharge.
What Stage Is My Melanoma?
Once a specialist diagnosis you with a type of melanoma, you’ll be assigned a stage based on how early or advanced the disease. Experts most commonly use the TNM system, which stands for tumor (T), nodes (N), and metastasis (M) to help determine your overall number stage.
T: Your doc will determine the thickness of your tumor, also known as the Breslow measurement. The thicker it is, the greater chance of spreading.
T1: greater than 1.0 mm thick
T2: between 1.0 and 2.0 mm thick
T3: between 3.0 and 4.0 mm thick
T4: greater than 4.0 mm thick
Your tumor is also checked for ulceration: a breakdown of the skin over the tumor. Ulcerated melanomas typically have a poorer prognosis.
N: This refers to whether or not the tumor has spread to the lymph nodes (hundreds of areas throughout your body that filter fluids).
N1: spread to one node or satellite tumor (near the node)
N2: spread to two or three nodes or satellites
N3: spread to four or more affected nodes or satellite
M: If the tumor has metastasized, it has spread to other parts of the body, most commonly the liver, brain, lungs, and bones. M0 means no metastasis, and M1 means the tumor has metastasized.
Using the TNM system, doctors then assign the cancer a stage from zero to four.
Stage 0: Very early stage melanoma. This is also known as melanoma in situ (which means in the original place). It’s contained to the surface layer of the skin.
Stage I: This stage can be broken down by 1A and 1B. Both can be with or without ulceration.
In 1A, the tumor is less than 1.0mm.
In 1B, the tumor is more than 1.0 mm, but less than 2.0 mm.
Stage II: The tumor may have spread down to the deeper layers of skin, but it hasn’t spread to other organs. There are three sub-categories here:
Stage IIA: The tumor is more than 1.0 mm, but less than 2.0 mm with ulceration, or more than 2.0, but less than 4.0 without ulceration.
Stage IIB: The tumor is more than 2.0 mm and less than 4.0 mm with ulceration, or more than 4.0 mm without ulceration.
Stage IIC: The melanoma is more than 4.0 mm with ulceration.
Stage III: Stage III melanoma has spread to nearby lymph nodes. It can be broken down into four more categories.
With Stage IIIA: The tumor is more than 1.0 mm and less than 2.0 mm, with or without ulceration, and has spread to up to three lymph nodes.
Stage IIIB: More than 1.0 mm, less than 2.0 mm, and may have also spread to small areas of the skin near the lymph nodes (satellite tumors) and reached one node. Or it’s more than 2.0 mm, but less than 4.0 mm without ulceration and reached one node, or there are satellite tumors, or it has spread to two or three nodes.
Stage IIIC: There is no sign of the primary tumor, but there may be satellite tumors and affected nodes, or it’s spread to four or more lymph nodes. Stage IIIC can also mean the tumor is no more than 4.0 mm with ulceration or thicker than 4.0 without and it has spread to satellite areas or reached nodes.
With Stage IIID, the tumor is thicker than 4.0 mm, ulcerated, and it has spread to four or more lymph nodes, or a cluster of lymph nodes, and there are satellite tumors.
Stage IV: The tumor can be any size and may or may not be ulcerated, but it has begun to metastasize, spreading to other organs.
Whatever kind of melanoma you have, or how advanced it is, know this: There are more treatment options available to you than ever before. Under the guidance of your doctor, you’ll start on the plan that makes sense for you.
General Information on Melanoma Types: Aim At Melanoma Alliance. (n.d.). Types of Melanoma. aimatmelanoma.org/about-melanoma/types-of-melanoma/
The Most Common Form of Melanoma: Melanoma Research. (2016). Superficial Spreading Melanoma (An Analysis of 97 702 cases Using the SEER database). journals.lww.com/melanomaresearch/Abstract/2016/08000/Superficial_spreading_an_analysis_of.11.aspx
The Most Aggressive Type of Melanoma: Journal of the National Cancer Institute. (2019). Distinct Clinicopathological and Prognostic Features of Thin Nodular Primary Melanomas: An International Study from 17 Centers. cdc.gov/pcd/issues/2019/18_0640.htm
Desmoplastic Melanoma: Journal of Cutaneous and Aesthetic Surgery. (2015). An Unusual Case of Desmoplastic Malignant Melanoma. ncbi.nlm.nih.gov/pmc/articles/PMC4411598/
Head and Neck Melanoma Treatment: American Academy of Dermatology. (n.d.) Treatment May Differ For Melanoma On The Head Or Neck. aad.org/diseases/skin-cancer/melanoma-treatment-differs-on-head-neck
Melanoma Staging: American Cancer Society. (n.d.) Melanoma Skin Cancer Stages. cancer.org/cancer/melanoma-skin-cancer/detection-diagnosis-staging/melanoma-skin-cancer-stages.html
An Early Stage of Melanoma: Melanoma Research. (2020). Estimated Risk of Progression of Lentigo Maligna to Lentigo Maligna Melanoma. journals.lww.com/melanomaresearch/Citation/2020/04000/Estimated_risk_of_progression_of_lentigo_maligna.10.aspx
A Rare Form of Melanoma: Preventing Chronic Disease. (2019). Melanoma Among Non-Hispanic Black Americans. cdc.gov/pcd/issues/2019/18_0640.htm