Bone Tissue: Structure and Function
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Melanoma is a serious malignant tumor that arises from the abnormal proliferation of melanocytes, the cells responsible for the synthesis of melanin, the pigment that gives color to our skin. This dangerous neoplasm is often linked to excessive exposure to ultraviolet (UV) rays from the sun and artificial sources, such as tanning lamps.
Melanocytes, found in the basal layer of the skin's epidermis, are the cellular elements responsible for producing melanin. This brown pigment, once transferred to keratinocytes (the predominant cells in the epidermis), not only gives color to our skin but also protects it from harmful UV rays. Melanocytes are sensitive to sunlight, and exposure to UV rays stimulates their melanin synthesis activity.
There are two types of melanin: eumelanin and pheomelanin. Eumelanin is the type that protects from sunlight and is responsible for the darkening of the skin. It is abundant in populations with darker skin tones and limited in light-skinned ones. On the other hand, pheomelanin is high in populations with very light complexions, gradually reducing in those with increasingly darker complexions.
Historically, melanoma was a rare cancer. However, in recent decades, there has been a significant increase in its incidence. This tumor can affect individuals of all ages, but it is more common in those over 60 years old. It is also more prevalent in the male population over the age of 50, but in younger age groups, women are more prone to developing the neoplasm.
Melanoma is more likely to occur among individuals with lighter skin tones, making white skin a significant risk factor. However, it is essential to note that any population worldwide has a more or less high risk of getting melanoma.
Melanoma, particularly cutaneous melanoma, represents only 4% of skin cancers. However, it is responsible for a significant proportion of deaths associated with skin cancer. Other types of skin cancer include basal cell carcinoma, squamous cell carcinoma, among others.
Melanoma typically originates from the uncontrolled proliferation of melanocytes in normal skin or nevi (skin moles). However, there is a remote possibility that it originates from the uncontrolled proliferation of melanocytes in the mucosa, eye, inner ear, or meninges.
Melanoma results from damage to the DNA contained in melanocytes. This damage alters the capacity for cell growth and division, causing the uncontrolled proliferation typical of melanocytes that constitute melanomas. The main cause of this DNA damage is excessive exposure to UV rays from sunlight and tanning lamps.
Certain factors can increase the risk of developing melanoma. These include:
There are four main types of cutaneous melanoma:
Melanoma can present as a newly formed nevus or an alteration of a pre-existing nevus. It generally has specific characteristics, which help in its recognition. Melanomas tend to have an irregular shape and edges and, in many cases, have a diameter greater than 6 millimeters. Other symptoms include changes in color, bleeding and formation of crusts, and feelings of itchiness and pain.
The diagnosis of melanoma usually begins with a physical examination and clinical history, followed by a biopsy on a sample of cells taken from the suspected area for a definitive diagnosis. In case of confirmed presence of melanoma, further tests may be necessary to establish whether and how the neoplasm has spread to other organs and tissues of the body.
The treatment of melanoma depends on its stage and the patient's general health status. The main treatments include surgery, targeted therapy, immunotherapy, chemotherapy, and radiotherapy. The goal of treatment is to remove the tumor, eliminate any residual tumor cells, and reduce the risk of recurrence.
As melanoma largely depends on modifiable factors, it is possible to control the risk of its appearance and try to reduce it. Preventive measures include avoiding excessive exposure to sunlight, using protective sunscreens, avoiding the use of tanning lamps, regularly checking your skin, and not ignoring any skin abnormality that appears suddenly. If you have a genetic or familial predisposition to melanoma, it is advisable to cover the parts of the body that are usually more exposed to light.
In conclusion, understanding melanoma, its causes, symptoms, treatment, and preventive measures can help in its early detection and successful management. Regular skin checks and immediate medical consultation in case of any suspicious skin changes are very important.