melanoma

Melanoma Cancer: Causes and Risk Factors

Melanoma:

Melanoma is the most dangerous type of skin cancer. It is the leading cause of death from skin disease. Currently it is the sixth most common cancer in both males and females.

melanoma

What is the cause and incidence of melanoma?

The melanoma develop when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations (genetic defects) that causes the skin cells to multiply rapidly and form malignant tumors.  These tumors originate in the pigment-producing melanocytes in the basal layer of the epidermis. Melanomas often resemble moles; some develop from moles. The majority of melanomas are black or brown, but they can also be skin-colored, pink, red, purple, blue or white. Melanoma is caused mainly by intense, occasional UV exposure (frequently leading to sunburn), especially in those who are genetically predisposed to the disease. Melanoma kills an estimated 8,790 people in the US annually.

  • If melanoma is diagnosed and treated early, it is almost always curable, but if it is not, the cancer can advance and spread to other parts of the body, where it becomes hard to treat and can be fatal. It is not the most common of the skin cancers, but it causes the most deaths. The American Cancer Society estimates that at present, about 120,000 new cases of melanoma in the US are diagnosed in a year. In 2010, about 68,130 of these were invasive melanomas, with about 38,870 in males and 29,260 in women.

Types of melanoma:

Melanomas fall into four basic categories. Three of them begin in situ — meaning they occupy only the top layers of the skin — and sometimes become invasive; the fourth is invasive from the start. Invasive melanomas are more severe, as they have penetrated deeper into the skin and may have spread to other areas of the body.

Superficial spreading melanoma is by far the most common type, about 70 percent of all cases. This is often seen in young people. This melanoma grows along the top layer of the skin for long time before it start to penetrate deeply.

The first sign is the appearance of a flat or slightly raised discolored patch that has irregular borders and is somewhat asymmetrical in form. The color varies, and you may see areas of tan, brown, black, red, blue or white. This type of melanoma can occur in a previously benign mole. The melanoma can be found almost anywhere on the body, but is most likely to occur on the trunk in men, the legs in women, and the upper back in both.

Lentigo maligna is similar to the superficial spreading type, as it also remains close to the skin surface for quite a while, and usually appears as a flat or mildly elevated mottled tan, brown or dark brown discoloration. This type of in situ melanoma is found most common involves elderly people, arising on chronically sun-exposed, damaged skin on the face, ears, arms and upper trunk. Lentigo maligna is the most common form of melanoma in Hawaii. When this cancer becomes invasive, it is called as lentigo maligna melanoma.
Acral lentiginous melanoma also spreads superficially before penetrating more deeply. It is relatively different from the others, though, as it usually appears as a black or brown discoloration under the nails or on the soles of the feet or palms of the hands. This type of melanoma is sometimes found in dark-skinned people, and often spread more quickly than superficial spreading melanoma and lentigo maligna. It is the most common melanoma in African-Americans and Asians, and the least common among Caucasians.

Acral lentiginous melanoma

nodular melanoma

Nodular melanoma is usually invasive at the time it is first diagnosed. The malignancy is recognized when it becomes a bump. It is usually black, but rarely it is blue, gray, white, brown, tan, red or skin tone.

The most frequent locations are the trunk, legs, and arms, mainly of elderly people, as well as the scalp in men. This is the most aggressive of the melanomas, and is found in 10 to 15 percent of cases.

Rarely, melanomas appear in the mouth, iris of the eye, or retina at the back of the eye. They may be found during dental or eye examinations. Although very rare, melanoma can also develop in the vagina, esophagus, anus, urinary tract, and small intestine.

The risk of developing melanoma increases with age. However, it is also frequently seen in young people.

amelanotic-melanoma

conjunctival_melanoma

Risk factors of melanoma:

You are more likely to develop melanoma if you:

  • Have fair skin, blue or green eyes, or red or blond hair
  • Live in sunny climates or at high altitudes
  • Spent a lot of time in high levels of strong sunlight, because of a job or other activities
  • Have had one or more blistering sunburns during childhood
  • Use tanning devices
  • Close relatives with a history of melanoma.
  • in contact with cancer-causing chemicals such as arsenic, coal tar, and creosote.
  • Certain types of moles (atypical dysplastic) or multiple birthmarks.
  • Weakened immune system due to disease or medication

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