Updated: September 29, 2019
Melanoma is a form of skin cancer that arises when pigment producing cells known as melanocytes mutate and become cancerous.
Most pigment cells which produces melanin are found in the skin. But melanoma can also occur in the eyes known as ocular melanoma and other parts of the body, including the tissues around the brain and spinal cord and the intestines. It is rare in people with darker skin.
It can be dangerous than the other forms of skin cancer as it is more likely to spread, or metastasize to other parts of the body, causing serious illness and death. Cutaneous or skin melanomas are very difficult to recognize. Most melanomas can be cured with relatively minor surgery if detected in early stage.
White ancestry, fair skin, light hair and light-colored eyes, a history of intense sun exposure, close blood relatives with melanoma, and moles that are unusually numerous, large, irregular, or funny looking are the risk factors for melanoma.
Melanomas can develop anywhere on the skin, but certain areas are more prone than others. It is most likely to affect the chest and the back in men where as in women, the legs are the most common affected area. Other common sites are the neck and face. Diagnose melanoma can be done by performing a biopsy.
Staging can be done depending on the thickness of tumor and how far the cancer has already spread. Tumor thickness is measured in fractions of millimeters and is called the Breslow's depth. It can be of five stages, ranging from from 0 to 4.
There are four types of melanoma which include:
This is the most common type of melanoma which often appears on the trunk or limbs. At beginning, the cells tend to grow slowly, before spreading across the surface of the skin. These melanomas are flat or barely raised and have a variety of colors. Such melanomas can be readily caught at an early stage and resolve over 1 to 5 years if they are detected and removed.
A malignant melanoma in situ called as in situ melanoma, refers to a very thin superficial spreading melanoma. It does not extend beyond the junction of the dermis and epidermis which is usually the normal location for melanocytes..
It is the second most common type, appearing on the trunk, head, or neck.
These melanomas are deeper and appears as blue,black to purplish lumps. They may evolve faster and may also be more likely to spread than other types. Untreated superficial spreading melanomas may become nodular and invasive.
This is less common, and tends to affect older people, especially in parts of the body that have been exposed to the sun over several years such as face. It starts as a Hutchinson's freckle, or lentigo maligna, which looks like a stain on the skin. It usually grows slowly and it less dangerous than other types. Lentigo maligna looks like a large, irregularly shaped or colored freckle and develops slowly.
This kind of melanoma is very rare. It usually appears on the palms of the hands, soles of the feet, or under the nails. It is more likely in people with darker skin and does not appear to be linked to sun exposure.
Other rarer forms of melanoma that may occur include subungual which appears under the nails, uveal or choroidal or ocular, oral or other mucosal areas such as the vulva or penis, or sometimes even inside the body such as the brain.
The early stages of melanoma may be hard to detect as with other forms of cancer. So it is important to check the skin actively for signs of change.
A changing spot or mole may be a problem, but does not necessarily every change means cancer. A mole may appear and then get bigger or become raised but still be only a mole. It is normal for many moles to start flat and dark, become raised and dark, and then later lose much of their color. This process takes many years.
The ABCDE examination of skin moles is also a way to reveal suspect lesions. It describes five simple characteristics to look out for in melanoma appearance:
As many normal moles and other benign lesions of the skin are not perfectly symmetrical in their shape or color, many a times it is difficult to identify a melanoma. Many spots, which have one or more features of the ABCDEs, are found as just ordinary moles and not melanomas. On the other hand even if some melanomas do not have this description but may still be spotted by a primary care physician or dermatologist. Not necessarily all melanomas have color or are raised on the skin. For example, Amelanotic melanomas have little or no color and may be confused with traumatized benign nevi or basal cell carcinoma. Desmoplastic melanoma may appear to be a thickened area of skin like a scar. Often melanoma is not painful unless traumatized. They are sometimes itchy, but this can not be considered as a symptoms for diagnosis.
If the skin changes are rapid or dramatic, the problem is considered as less serious. When changes such as pain, swelling, or even bleeding come on rapidly, within a day or two, they are likely to be caused by minor trauma. If a spot changes rapidly and then appears the way it was within a couple of weeks, or falls off altogether, there is nothing serious. However, if a new spot is identified or changing or that doesn't look like other spot, it should be evaluated by a doctor.
Excessive exposure to the ultraviolet (UV) radiation of sun is the main cause of melanoma.
However, the following factors are associated with an increased incidence of skin cancer:
Only high sun exposure and sunburn are avoidable out of all these factors. Avoiding overexposure to the sun and preventing sunburn can significantly lower the risk of skin cancer. Avoid tanning beds as well as they are also a source of damaging UV rays.
By regularly examining moles and other colored blemishes and freckles a person can detect the early signs of melanoma by themselves. Any changes in the appearance of the skin should be examined by a doctor.
As most of the melanomas in men occur on the back, it should be checked regularly. A partner, family member, friend, or doctor can help check the back and other areas that are hard to see. The ABCDE checklist described above can help with the diagnosis.
Microscopic or photographic tools can be used by a doctor to see a lesion in more detail. The patient will be referred to a cancer specialist and a biopsy can be done to test the lesion where a sample of the lesion is taken for examination in the laboratory under a microscope in case skin cancer is suspected.
The best biopsy is one that removes the entire extent of the visible tumor to diagnose melanoma. MRIs, PET scans, CT scans, chest X-rays, or other X-rays of bones are recommended when there is a concern of metastasis. These test are also recommended for patients who have had thicker tumors diagnosed or who already have signs and symptoms of metastatic melanoma. Blood tests of liver, and any other studies that will assist in staging or determining the extent of spread of the tumor.
Surgery is the most common treatment for melanoma. It involves removing the lesion and some of the normal tissue around it depending on tumor thickness, location and your age. A biopsy may be taken at the same time.
A skin graft may be necessary if melanoma covers a large area of skin. A lymph node biopsy may be performed in case the cancer have penetrated into the lymph nodes. when the melanoma has spread to other parts of the body, treatments like immunotherapy or chemotherapy are sometimes recommended. Sometimes photodynamic therapy, which uses a combination of light and drugs, and radiation are used which is very rare.
Avoiding excessive exposure to ultraviolet radiation of sun can reduce the risk of skin cancer.
The following steps may help protect the UV radiation:
Applying a sunscreen lotion does not mean you can spend longer in the sun. Sun exposure should still be limited, where ever possible. People who work outdoors should take precautions to minimize exposure by finding shade. Tanning booths, lamps, and sunbeds should be avoided. Anyone who is at a higher risk of getting the disease, such as anyone with a close relative who has melanoma, should be screened by a doctor for melanoma. Individuals should get their skin checked on a regular basis.
Prognosis of a melanoma depends on tumor thickness. The thinner the melanoma, the better the prognosis. If it has spread to lymph nodes or other body locations, the prognosis is poor. Thin melanomas, those measuring less than 0.8 millimeters, generally gets cure with local surgery alone. Thicker melanomas, takes more time and combination of therapies to get cure.