What is melanoma?
Melanoma is a disease of the skin in which cancer cells are found in the melanocytes, the cells that produce color in the skin or pigment known as melanin. Melanoma usually occurs in adults, but it may occasionally be found in children and adolescents. Melanoma also may be called cutaneous melanoma or malignant melanoma. Melanoma is the rarest, but most virulent, form of skin cancer.
Melanoma is a more serious type of cancer than the more common basal cell cancer or squamous cell cancer. Although the incidence of melanoma is lower than other types of skin cancer, it has the highest death rate and is responsible for 75 percent of all deaths from skin cancer.
Where is melanoma most often found?
Melanoma most often appears on fair-skinned men and women, but people with other skin types can be affected. Rarely, melanomas can form in parts of the body not covered by skin, such as the eyes, mouth, vagina, large intestine and other internal organs.
What are the risk factors for melanoma?
Persons with the following characteristics may be at an increased risk for melanoma:
- Blond or red hair.
- Blue eyes.
- Fair complexion.
- Family history of melanoma.
- A changed or changing mole.
- Many ordinary moles (more than 50).
- Many freckles.
- An immunosuppressive disorder.
- Dysplastic nevi.
- Sun exposure – the amount of time spent unprotected in the sun directly affects your risk of skin cancer.
- Inability to tan.
Dark-brown or black skin is not a guarantee against melanoma. African Americans can develop this cancer, especially on the palms of the hands, soles of the feet, under nails or in the mouth.
What are the symptoms of melanoma?
The following are the most common symptoms of melanoma; however, each individual may experience symptoms differently. Symptoms may include:
- Change in the size, shape or color of a mole.
- Oozing or bleeding from a mole.
- A mole that feels itchy, hard, lumpy, swollen or tender to the touch.
Because most malignant melanoma cells still produce melanin, melanoma tumors are often shaded brown or black. Melanoma also can appear on the body as a new mole. Men most often develop melanoma on the area of the body between the shoulders and hips, or on the head or neck. Women most often develop melanoma on the arms and legs. However, melanoma can spread quickly to other parts of the body through the lymph system or through the blood. Like most cancers, melanoma is best treated when it is diagnosed early.
The symptoms of melanoma may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
Distinguishing benign moles from melanoma
To prevent melanoma, it is important to examine your skin on a regular basis and become familiar with moles and other skin conditions in order to better identify changes. According to recent research, certain moles are at a higher risk for changing into malignant melanoma. Moles that are present at birth and atypical moles have a greater chance of becoming malignant. Recognizing changes in your moles, by following this ABCD Chart, is crucial in detecting malignant melanoma at its earliest stage.
The warning signs are:
Normal mole / melanoma
When half of the mole does not match the other half.
When the border (edges) of the mole are ragged or irregular.
When the color of the mole varies throughout.
If the mole's diameter is larger than a pencil's eraser.
Photographs used by permission: National Cancer Institute
Melanomas vary greatly in appearance. Some melanomas may show all of the ABCD characteristics, while other may only show changes in one or two characteristics. Always consult your physician for a diagnosis.
How is melanoma diagnosed?
Medical examinations and tests are used to determine if a suspicious area is melanoma skin cancer. In addition to a complete medical history, including family history, questions are asked about the marking on the skin, such as when you first noticed it, as well as if and how it has changed in size or appearance.
The suspected area as well as the rest of your body is examined, noting the size, shape, color, texture and if there is bleeding or scaling. A skin sample will probably be examined by a biopsy. The biopsy procedure chosen depends on the site and size of the affected area.
Types of biopsies
The different types of biopsies include the following:
- Excisional or incisional biopsy – often used when a wider or deeper portion of the skin is needed. Using a scalpel (surgical knife), a full thickness of skin is removed for further examination, and the wound is sutured (with surgical thread).
When the entire tumor is removed, it is called excisional biopsy technique. If only a portion of the tumor is removed, it is called incisional biopsy technique. Excisional biopsy is often the method preferred when melanoma is suspected.
- Fine needle aspiration (FNA) biopsy – involves using a thin needle to remove very small pieces from a tumor. Local anesthetic is sometimes used to numb the area, but the test rarely causes much discomfort and leaves no scar.
FNA is not used for diagnosis of a suspicious mole, but may be used to biopsy large lymph nodes near a melanoma to see if the melanoma has metastasized (spread). A computed tomography scan (CT or CAT scan), an X-ray procedure that produces cross-sectional images of the body, may be used to guide a needle into a tumor in an internal organ such as the lung or liver.
- Punch biopsy – involve taking a deeper sample of skin with a biopsy instrument that removes a short cylinder, or “apple core,” of tissue. After a local anesthetic is administered, the instrument is rotated on the surface of the skin until it cuts through all the layers, including the dermis, epidermis and the most superficial parts of the subcutis (fat).
- Shave biopsy – involves removing the top layers of skin by shaving it off. Shave biopsies also are performed with a local anesthetic.
Skin biopsy – involves removing a sample of skin for examination under the microscope to determine if melanoma is present. The biopsy is performed under local anesthesia. The patient usually just feels a small needle stick and slight burning for about one minute, with a little pressure, but no pain.
Biopsies are obtained from the different skin layers:
- A shave biopsy generally involves obtaining tissue specimens from the thin outer layer of skin, called the epidermis.
- A punch biopsy generally involves obtaining tissue specimens from the epidermis. However, in some cases, a punch biopsy involves the dermis and subcutaneous tissue.
- An excisional biopsy generally involves obtaining tissue specimens from the deepest layer of skin, called the subcutaneous tissue.
What is staging?
When melanoma is found, more tests will be done to find out if the cancer cells have spread to other parts of the body. This step is called staging, and is necessary before treatment for the cancer can begin.
What are the stages for melanoma?
The National Cancer Institute stages of melanoma are:
Abnormal cells are found only in the outer layer of skin and have not invaded deeper tissue.
Cancer is found in the outer layer of the skin (epidermis) and/or the upper part of the inner layer of skin (dermis), but it has not spread to nearby lymph nodes. The tumor is less than 1.5 millimeters (1/16 of an inch) thick.
The tumor is larger than 1.5 millimeters. It has spread to the lower part of the inner layer of skin (dermis), but not into the tissue below the skin or into nearby lymph nodes.
The tumor has spread to the body tissue below the skin and to nearby lymph nodes.
The tumor has spread to other organs or to lymph nodes far away from the original tumor.
Always consult your physician for more information regarding the staging of melanoma.