Melanoma is a type of cancer that begins in the skin. It occurs in cells called melanocytes that produce melanin, the brown pigment that is responsible for the color of our skin. Melanoma is when melanocytes become cancerous, grow and invade other tissues.

Melanoma is the most serious form of skin cancer. While it accounts for only about 4 percent of skin cancers, it causes about three-quarters of all skin cancer deaths. Melanoma can be completely treated when detected early, but fatal if allowed to grow and spread.

Signs and Symptoms
Types of Skin Cancer
Causes of Melanoma
Risk Factors for Melanoma
Screening and Diagnosis
Staging Melanoma
Prevention
FAQs

Signs and Symptoms

Changes in the skin are the most common sign of early melanoma. A mole or skin lesion that grows or changes shape or color, a new spot or growth, any pigmented (more darkly colored) areas that look different from other moles, or a sore that does not heal – all require prompt medical attention. Use this simple “ABCDE” rule to recognize the warning signs of melanoma:

• Asymmetry: One half of the mole does not match the other half
• Border irregularity: The edges of the mole are ragged, notched or blurred
• Color: The pigmentation of the mole is not consistent. There are different shades of tan, brown or black, and sometimes patches of red, blue or white, giving it a mottled appearance.
• Diameter: Melanomas are usually at least 6mm in diameter when diagnosed (about the size of a pencil eraser), but they can be smaller.
• Elevation: A mole becomes elevated or raised above the surface of the surrounding skin.

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Types of Skin Cancer

Skin cancers are divided into two major types: non-melanoma and melanoma.

Non-melanomas

Nonmelanoma skin cancers are the most common cancers of the skin; in fact, they are more common than any other type of cancer. They are referred to as nonmelanomas because they develop from skin cells other than melanocytes. And because they seldom metastasize (spread), they are treated differently than melanoma. There are two common nonmelanomas:

•  Basal cell carcinoma: This type of skin cancer accounts for 70 to 80 percent of all skins cancers in men and 80 to 90 percent in women. It usually develops on areas that are exposed to the sun, like the head and neck. Basal cell carcinoma begins in the lowest layer of the skin, called the basal cell layer. It is slow growing and generally does not spread to lymph nodes or distant parts of the body. If left untreated, however, it can invade nearby bone or other tissues beneath the skin. Once found mostly in middle-aged or older people, basal cell carcinoma is being seen more frequently in younger people, probably due to increased sun exposure.
• Squamous cell carcinoma: About 10 to 30 percent of all skins cancers are squamous cell carcinomas. They most often appear on sun-exposed areas including the face, ear, neck, lip, and back of the hands. Squamous cell cancer tends to be more aggressive than basal cell; it is more likely to invade fatty tissues beneath the skin, and slightly more likely to spread to lymph nodes or distant parts of the body (although this is still fairly uncommon).

Hidden Melanomas 

Melanomas usually develop on the skin, but they sometimes occur on other parts of the body that are not easily or regularly examined for skin cancer, such as the mouth, eye, inside the nose or under the fingernail. While these “hidden” melanomas are relatively uncommon, they are important to know about because treatment is most effective when they are detected early.

It is possible to detect these melanomas in their earliest stages by carefully examining these “hidden” areas yourself. For those areas that you cannot easily see, routine dental, gynecologic and ophthalmologic visits should include examination for these types of pigmented (more darkly colored) changes in your skin:

• Subungual melanoma. “Subungual” means under a nail. The most common sign of this melanoma is a dark streak underneath the nail (usually of the thumb or big toe) that is not related to a bruise. This form of melanoma accounts for about 2 percent of melanomas in Caucasians and 30 to 40 percent of melanomas in non-Caucasians. It appears most often in people over age 50. You should seek medical attention, regardless of your race and age, if you see the following underneath a nail:
• Black streak
• Wide or variegated (mottled) brown streak
• Nail bed is raised or separated from nail bed
• Skin next to the nail darkens
• Nail appears deformed or as if it is being destroyed
• Mucosal melanoma. Melanomas can occur in the mucosal tissue (mucous membrane) that lines the nose, mouth, female genitals, anus, urinary tract and esophagus. While skin cancers in these locations are rare, they tend to be advanced when diagnosed since the mucosal tissues are difficult to examine. In addition, treatment can be delayed because early signs and symptoms can be minor and often are ignored or misinterpreted.
• The nose and mouth are the most common places for mucosal melanomas to develop. Early signs and symptoms include nosebleeds and nasal stuffiness, a pigmented (more darkly colored) mass in the mouth and pain when swallowing, and inflammation of the inner ear.
• A very small percentage of melanomas occurs in the vulva and/or vagina, and are usually detected during a gynecologic exam. The most common signs and symptoms are vaginal discharge, bleeding, itching and pain, which can be mistaken for vaginal infection or menstrual irregularity.
• Melanoma of the anus (the medical term is anorectal, referring to both the anus and rectum) usually causes no symptoms in the early stages. In advanced cases, the most common symptom is rectal bleeding. A painful rectal mass, which can be mistaken for a hemorrhoid, may also occur.
• Melanoma of the urinary tract (urethral melanoma) also causes no symptoms in the early stages. Later signs and symptoms, which occur in both men and women, include blood in the urine, painful urination, frequent urination, and straining to urinate but passing little urine.
• Melanoma in the esophagus is extremely rare. Symptoms are not noticeable until the cancer is advanced and include difficulty swallowing, regurgitation, pain and bleeding in the esophagus.
• Ocular melanoma. “Ocular” refers to the eye, where melanoma can develop in the lining of the eyelid or the thin, colored coating in the eyeball. Signs and symptoms of ocular melanoma include a scratchy feeling under the eyelid and a dark spot on the eyeball.

Cutaneous melanomas

Cutaneous melanoma is the medical term for melanoma that starts in the melanocyte cells of the skin (“cutaneous” refers to the skin). There are four clinical types of cutaneous melanoma, also referred to as malignant melanoma:

• Superficial spreading melanoma (SSM) is the most common type of melanoma in the U.S., accounting for about 70 percent of all melanoma cases. It can occur at any age, is seen slightly more often in women than in men, and is the leading cause of cancer death in young adults. While it can appear anywhere on the skin’s surface, SSM is most commonly seen on the legs in women, and between the neck and pelvis in men.
  
  In its early stages, SSM usually looks like a freckle that is spreading sideways. Over time, the pigmentation (color) of the lesion may darken and the lesion may grow, developing increasingly irregular borders. It also may look inflamed or the area around the lesion may itch. SSM can progress quickly, so if you notice these signs and symptoms, see a doctor right away.
• Nodular melanoma (NM) is the most aggressive type of melanoma. It accounts for about 15 percent of all melanomas in the U.S. It is most often seen in people over age 60, but can develop at any age. It is more common in men than women, and can appear anywhere on the body.
  
  NM is different from other melanomas in three ways: it tends to grow deeper (down into the skin) rather than wider; its development cannot be easily seen; and it may occur in a spot where a mole did not exist before. As a result, it can take longer for someone to be aware of NM, so it is often diagnosed when it is more advanced. While NM is usually darkly colored, some NM lesions can be light brown or even colorless, which also makes them hard to detect. If you notice a lesion appearing where one did not exist before, have it examined by a doctor as soon as possible.
• Acral-lentiginous melanoma (ALM) is the most common type of melanoma in Asians and people with dark skin. It is sometimes called a “hidden” melanoma because it occurs on parts of the body not routinely examined, such as the palms of the hand, soles of the feet, mucous membranes in the mouth, nose and female genitals, and beneath or near fingernails and toenails. As a result, ALM can be overlooked until it is advanced.
  
  As most ALM tumors grow, their shape and color become more irregular. Some ALM lesions, however, can be light in color or even colorless. The surface of the tumor may remain flat while the cancer grows deeper into the skin. An ALM on the sole of the foot can be mistaken for a plantar wart that makes walking painful. Be sure to see a doctor promptly if you notice a bruise that does not fade or comes and goes; a new, enlarging or very dark streak in your nail (and you did not bruise your nail recently); a pigmented (colored) mass in the mouth; or nosebleeds and nasal stuffiness.
• Lentigo maligna melanoma (LMM) most commonly occurs on the faces of middle-aged or elderly people with sun-damaged skin. In its earliest, most treatable stages, LLM may be mistaken for a benign (non-cancerous) “age spot.” It begins as a flat, spreading patch with an irregular border and varied brown colors. As LLM develops, however, both the color and border become more irregular. This can occur slowly, over 10 to 15 years, or it can happen within weeks or months. Left untreated, the cancer thickens, growing deeper into the skin. Dark nodules (lumps that you can feel by touch) may appear. See a doctor if you have a pigmented patch of skin, especially one with an irregular border.

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Causes of Melanoma

Too much unprotected exposure to ultraviolet (UV) radiation is the main cause of melanoma. UV radiation is found in natural sunlight as well as tanning booths and lamps.

UV rays damage DNA, the material that makes up our genes. Genes control the growth and overall health of all our cells, including skin cells. If genetic damage is severe, a normal skin cell may begin to grow abnormally, in the out-of-control way of cancer cells.

Not all melanomas are related to UV radiation, however. Other possible causes include gene mutation, heredity and immune system deficiencies.

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RiskFactors for Melanoma

A risk factor is anything that increases a person’s chance of getting a disease such as cancer. Having one or even several risk factors does not mean someone will get the disease, but it does make the risk greater. These are the most common risk factors for melanoma:

Fair Skin, Freckles and Light Hair

Caucasians have a 20-times greater risk of melanoma than African-Americans. This is because skin pigment (melanin) has a protective effect, and dark-skinned people have more melanin. In addition, certain Caucasians are at greater risk than others, especially those with red or blonde hair, or fair skin that freckles or burns easily. A Caucasian with fair skin is four times more at risk of developing melanoma as a Caucasian with olive skin.

History of Sunburn

If you have had five or more sunburns, it doubles your risk of developing skin cancer.

Excessive Sun Exposure

Sun exposure is the major risk factor for all skin cancers, including melanoma. Sunlight, as well as the artificial light from tanning booths and lamps, contains ultraviolet (UV) radiation that can damage the genes in skin cells. Children or teenagers who get intense sun exposure are at risk for developing melanoma years or even decades later.

Sunny or High-Altitude Climates

People who live in geographic regions closer to the equator (such as the southern U.S.), where sunlight is strongest, are more likely to develop melanoma than those who live in northern regions. The sun also is stronger at higher elevations, exposing you to more UV radiation and increasing skin cancer risk.

Moles

Having one atypical mole (called a dysplastic nevus) doubles the chances of developing melanoma. Atypical moles are unusual moles that are usually larger than normal moles, variable in color and often have irregular borders. They may occur anywhere on the body. In addition, having 50 or more moles, even if they are normal, also increases the risk for developing melanoma.

Family History

The risk of melanoma is greater if you have a mother, father, brother, sister or child who has been diagnosed with the disease. An estimated 10 percent of people with melanoma have a family history of melanoma.

Weakened Immune System

Having a weakened immune system increases the risk for many diseases, including skin cancer. This includes people with other types of cancers, chronic leukemias and HIV/AIDS. People being treated with medications that suppress the immune system, such as organ transplant patients, also are at increased risk.

Environmental/Occupational Hazards

• Exposure to hazardous environmental chemicals such as herbicides has been shown to increase the risk of melanoma. Occupational exposures to coal tar, pitch, creosote, arsenic compounds or radium also has been linked to skin cancer.

Genetic Disorder

There is a rare inherited condition called xeroderma pigmentosum (XP) that causes extreme sensitivity to sunlight. People with XP are less able to repair skin damage caused by UV light, greatly increasing their risk of developing melanoma.

Past History

A person who has already had melanoma has a significantly increased risk of developing the disease again.

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Screening and Diagnosis

Screening Recommendations

Regular examination of your skin by both you and your doctor increases the chance of finding melanoma early, in its most treatable stages. The Skin Cancer Foundation recommends an annual screening by your physician. Regular skin checks by a doctor also are especially important for people who have already had skin cancer. In addition, everyone should be familiar with their own pattern of moles, blemishes, freckles and other marks on the skin so they can be aware of changes during monthly self-examinations.

Diagnosing Melanoma

A new spot or growth on the skin (often referred to as a lesion), or changes in an existing mole raises the possibility of melanoma. These are the usual steps involved in diagnosing melanoma:

History and physical examination. Your doctor to will ask questions about symptoms and risk factors to earlier section on Risk Factors), when the skin lesion first appeared and if it has changed in size or appearance, and family history of melanoma. The rest of your body will be examined for spots and moles. The doctor also will examine lymph nodes in areas near the suspicious lesion on your skin. Enlarged lymph nodes might mean the spread of a melanoma to these glands.

Biopsy. If your doctor suspects melanoma, a sample of the skin is removed in a procedure called a biopsy. The sample is sent to a laboratory where a pathologist examines it under a microscope to confirm the diagnosis.

Imaging studies. A chest x-ray may be taken to see whether the melanoma has spread to the lungs. Other imaging techniques – such as computed tomography (CT) scans, magnetic resonance imaging (MRI) and positron emission tomography (PET) – may also be used to determine if the melanoma has spread to other organs or lymph nodes.

Sentinel lymph node mapping and biopsy. If melanoma has spread, the sentinel lymph nodes (the lymph nodes closest to the tumor) are usually the first place it will go. The appropriate sentinel lymph node is found through a process called mapping, then it is removed for examination under a microscope. If melanoma cells are found in the sentinel lymph node, the remaining lymph nodes in the same area are surgically removed. If a lymph node near a melanoma is abnormally large, a biopsy of this lymph node is performed and the sentinel node procedure may not be required.

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Staging Melanoma

Staging is the process of describing how much a cancer has metastasized (spread). It describes the size of the tumor and whether it has spread, giving your healthcare team a standard way to summarize the extent of the cancer. It also helps to determine the most appropriate course of treatment.

Thickness and Depth

When a skin biopsy is performed, the pathologist measures the thickness of the melanoma under the microscope with a device called a micrometer. This technique is called the Breslow measurement. It is important to measure the thickness because it is believed to be one of the best ways to determine the outlook for survival (prognosis). The thinner the melanoma, the better the prognosis.

Another system called the Clark level describes the thickness of a melanoma in terms of which layer of the skin it has penetrated or “invaded.” The Clark level of a melanoma uses a scale of I to V, with the higher numbers indicating a deeper melanoma. The Clark level system relates the degree of depth of melanoma into the skin to the 5-year survival rate after surgical removal of the melanoma.

Metastasis (Spread)

The American Joint Committee on Cancer (AJCC) staging system is what doctors commonly use to describe the extent of melanoma. In this TNM (Thickness, Node, Metastasis) staging system, the cancer is assigned a T, N and M category:

• The T category is based on the tumor’s thickness, or depth, and whether the layer of skin covering the melanoma is gone (known as ulceration).
• The N category refers to whether the melanoma has spread to the lymph nodes.
• The M category indicates whether the cancer has metastasized to distant organs.

The TNM information is then combined according to a process called stage grouping to assign the cancer a stage. Stages are described using zero (0) and Roman numerals from I to IV:

• Stage 0: The melanoma is in situ, which means that it is confined to the epidermis (the outer layer of the skin).
• Stage IA: The melanoma is 1.0 mm (about 1/25 inch) or less in thickness and there is no ulceration (the layer of skin covering the melanoma is not gone). It appears to be localized in the skin and has not spread.
• Stage IB: The melanoma is 1.0 mm thick and is ulcerated, or it is between 1.01 and 2.0 mm and not ulcerated. It appears to be localized in the skin and has not spread.
• Stage IIA: The melanoma is between 1.01 and 2.0 mm in thickness and is ulcerated, or it is between 2.01 and 4.0 mm and not ulcerated. It appears to be localized in the skin and has not spread.
• Stage IIB: The melanoma is between 2.01 and 4.0 mm in thickness and is ulcerated, or it is thicker than 4.0 and not ulcerated. It appears to be localized in the skin and has not spread.
• Stage IIC: The melanoma is thicker than 4.0 and is ulcerated. It appears to be localized in the skin and has not spread.
• Stage III: The melanoma has spread to lymph nodes nearest to the affected skin area. There is no distant spread.
• Stage IV: The melanoma has spread beyond the original area of the skin and nearby lymph nodes to other organs, or to distant areas of the skin or lymph nodes.

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Prevention

Protecting yourself from the sun’s damaging rays can prevent most skin cancers. Research also shows that sun protection may also decrease the chances of a skin cancer coming back (recurring) if you have had skin cancer before. The most effective strategy is to limit unprotected exposure to the sun, especially between 10 a.m. and 4 p.m., when the sun’s UV rays are the strongest. Some other tips:

• Avoid deliberate tanning. Lying in the sun results in a 1 in 5 chance of developing skin cancer. Tanning booths and sunlamps should also be avoided since they produce UV radiation, too.
• “Slop” on sunscreen. Generously apply sunscreen with an SPF (Sun Protection Factor) of at least 15 to all exposed skin every day, even when it is cloudy. The sunscreen also should be what is called “broad spectrum” (it provides protection from ultraviolet A and ultraviolet B rays). The American Academy of Dermatology recommends using one ounce – enough to fill a shot glass – to cover the exposed areas of the body properly. Remember ears, nose, neck, hands and toes. Reapply after being in water or sweating.
• Wear protective clothing. This includes long-sleeved shirts, pants, wide-brimmed hat and wrap-around sunglasses.
• Use extra caution when you are near water, snow and sand. They reflect the sun’s damaging rays and increase the risk of sunburn.
• Protect children from the sun. Use the measures listed above to protect children from sun exposure, especially since they tend to spend more time outdoors and can burn more easily.
• Recognize abnormal moles and have them removed. Perform regular self-examinations and, if you find an unusual or changing mole, see your doctor right away.

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