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Melanoma Information
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To understand melanoma, it is helpful to know about the skin and about melanocytes—what they do, how they grow, and what happens when they become cancerous. |
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The skin has three layers:
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About the Epidermis |
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The outermost part of the epidermis is called the stratum corneum, or horny layer. It is composed of dead keratinocytes that are continually shed. Below the stratum corneum are layers of living keratinocytes, also called squamous cells. These cells are flat and scale-like and form an important protein called keratin, which contributes to the skin’s ability to protect the rest of the body. The lowest part of the epidermis, under the squamous cells, is formed by basal cells. These round cells continually divide to form new keratinocytes, which replace older keratinocytes that wear off the skin’s surface. The lower part of the epidermis also contains melanocytes. These skin cells produce the protective pigment called melanin, which give a tan or brown color to the skin and helps protect the deeper layers of the skin from the harmful effects of the sun. |
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About the Dermis |
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The middle layer, called the dermis, contains blood vessels, lymph vessels, hair follicles, nerves and glands, help in place by a protein called collagen. Some of these glands produce sweat, which helps regulate body temperature. Other glands produce sebum, an oily substance that helps keep the skin from drying out. Sweat and sebum reach the skin’s surface through tiny openings called pores. |
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About the Subcutis |
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The deepest layer beneath the skin is called the subcutis. The subcutis and the lowest part of the dermis form a network of collagen and fat cells. The subcutis conserves heat and has a shock-absorbing effect that helps protect the body’s organs from injury. |
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Melanocytes, Moles, and Tumors |
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Melanocytes produce melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes produce more pigment, causing the skin to tan, or darken. Sometimes, clusters of melanocytes and surrounding tissue form noncancerous growths called moles (also called a nevus). Moles are very common. Most people have between 10 and 40 moles. Moles may be pink, tan, brown, or a color that is very close to the person’s normal skin tone. People who have dark skin tend to have dark moles. Moles can be flat or raised. They are usually round or oval and smaller than a pencil eraser. They may be present at birth or may appear later on—usually before age 40. They tend to fade away in older people. When moles are surgically removed, they normally do not return. Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body. Normally, cells grow and divide to form new cells, as the body needs them. When cells grow old, they die, and new cells take their place. Sometimes this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor. Malignant tumors are cancer:
Cells from malignant tumors can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system. That is how cancer cells spread from the original cancer (the primary tumor) to form new tumors in other organs. The spread of cancer is called metastasis. Different types of cancer tend to spread to different parts of the body. |
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About Skin Cancer |
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There are three major types of skin cancer:
You have been diagnosed with melanoma which is a type of skin cancer that begins in skin cells called melanocytes (pigment cells). Most pigment cells are in the skin; when melanoma starts in the skin, the disease is called cutaneous melanoma. Melanoma may also occur in the eye (ocular melanoma or intraocular melanoma). Rarely, melanoma may arise in the meninges, the digestive tract, lymph nodes, or other areas where melanocytes are found. This information refers to cutaneous melanoma only. Melanoma is more aggressive than basal cell skin cancer or squamous cell skin cancer. Melanoma is one of the most common cancers. The chance of developing it increases with age, but this disease affects people of all ages. It can occur on any skin surface. Melanoma is rare in people with dark skin. When melanoma spreads, cancer cells may show up in nearby lymph nodes. Groups of lymph nodes are found throughout the body. Lymph nodes trap bacteria, cancer cells, or other harmful substances that may be in the lymphatic system. If the cancer has reached the lymph nodes, it may mean that cancer cells have spread to other parts of the body such as the liver, lungs, or brain. In such cases, the cancer cells in the new tumor are still melanoma cells, and the disease is called metastatic melanoma. |
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Staging Melanoma |
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If the diagnosis is melanoma, your doctor needs to learn the extent, or stage, of the disease before planning treatment. Staging is a careful attempt to learn:
Your doctor may remove nearby lymph nodes to check for cancer cells. The doctor also does a careful physical exam and, if the tumor is thick, may order chest x-rays, blood tests. There are no specific blood tests for metastatic melanoma, but sometimes a blood LDH level might be helpful. Blood LDH levels can be a marker for widespread melanoma. LDH (lactate dehydrogenase) is an enzyme found in the blood that may be higher than normal when a lot of cancer cells are present or when the liver has been damaged by cancer. |
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Stages of Melanoma |
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The following stages are used for melanoma: Stage 0: In stage 0, the melanoma cells are found only in the outer layer of skin cells and have not invaded deeper tissues. Stage I: Melanoma in stage I is thin:
Stage II: The tumor is at least 1 millimeter thick:
Stage III: The melanoma cells have spread to nearby tissues:
Stage IV: The melanoma cells have spread to other organs, to lymph nodes, or to skin areas far away from the original tumor. Recurrent: Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may have come back in the original site or in another part of the body. |
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Prognosis |
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Certain factors affect prognosis (chance of recovery) and treatment options. The prognosis and treatment options depend on:
Although many people are successfully treated, melanoma can recur. |
What Are the Treatment Options? |
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Melanoma may be treated with:
At any stage of disease, you may have treatment to control pain and other symptoms of the cancer, to relieve the side effects of therapy, and to ease emotional and practical problems. This kind of treatment is called palliative care, supportive care, or symptoms management. |
The skin is the body’s largest organ. It protects against heat, sunlight, injury, and infection. It helps regulate body temperature, stores water and fat, and produces vitamin D.
