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From skin to eyes: How does melanoma appear in unexpected places?
Melanoma, the most dangerous type of skin cancer, originates in melanin-producing cells, called melanocytes. Although melanoma usually develops on the skin, it can rarely develop in the mouth, intestines, or eyes (uveal melanoma). Studies show that melanoma most often occurs on the legs in women, while in men it mainly occurs on the back. The medical community often refers to melanoma as malignant melanoma, but experts emphasize that there is no such term as "benign melanoma" and therefore recommend avoiding the redundant term "malignant melanoma." About 25% of melanomas develop from moles, which may change in size, have irregular borders, change in color, itching, or skin breakdown.
The main cause of melanoma is ultraviolet (UV) exposure, and the risk is greater in people with low levels of melanin. This UV light can come from sunlight or other sources, such as tanning equipment.
Some people with many moles, a family history of the disease, and poor immune function are at higher risk. Additionally, some rare genetic disorders, such as xeroderma, can increase your risk. The pathological diagnosis is usually established by analysis of a biopsy of a suspicious skin lesion. Some studies suggest that avoiding UV rays and using sunscreen when in sunlight with strong UV rays may help prevent melanoma.
Treatment usually involves surgery to remove the melanoma and any potentially affected tissue nearby. For people with larger lesions, testing of nearby lymph nodes may also be done to check for spread. Once the disease has not metastasized, most people can be cured. For those whose disease spreads, immunotherapy, biological therapy, radiation therapy, or chemotherapy may improve survival.
According to statistics, in the United States, the five-year survival rate for localized disease is 99%, when the disease spreads to the lymph nodes it is 65%, and in the case of distant spread it drops to 25%. How quickly a melanoma can return or spread depends on its thickness, the rate at which its cells divide, and whether the surface skin is broken.
As of 2012, there were 232,000 new cases of melanoma worldwide; in 2015, there were 3.1 million active cases, resulting in 59,800 deaths.
Globally, melanoma rates are highest in Australia and New Zealand, with high rates also seen in Northern Europe and North America, but relatively low in Asia, Africa and Latin America. In the United States, melanoma is approximately 1.6 times more common in men than in women. The incidence of melanoma has been increasing since the 1960s, particularly in areas where the predominantly European population resides.
Early Signs and Causes
Early signs of melanoma are often changes in the shape or color of an existing mole, or a new bump. In advanced stages of the disease, the mole may itch, ulcerate, or bleed. Early signs of melanoma can be remembered using the mnemonic "ABCDEEFG", which includes asymmetry, irregular borders, color changes, diameter greater than 6 mm, and evolution over time. It is worth noting that nodular melanoma has its own classification criteria:
It has bumps above the skin's surface that are firm to the touch and grow over time.
Melanoma metastases may cause nonspecific paraneoplastic symptoms, including anorexia, nausea, vomiting, and fatigue. Spread of early-stage melanoma, while possible, is relatively rare; less than one in five melanomas diagnosed early will metastasize to other sites. Brain metastases are particularly common in patients with metastatic melanoma, which may also spread to the liver, bones, abdomen, or distant lymph nodes.
Treatment and prospects
There are many treatment options for melanoma, including surgical removal, immunotherapy, and chemotherapy. For cases discovered early, the survival rate is relatively high, but as the disease progresses, the effectiveness of treatment gradually decreases. In cases where the disease spreads to lymph nodes and distant organs, the patient's survival is affected.
Many melanomas harbor activating mutations that affect the structure of the B-Raf protein, leading to sustained signaling through the Raf to MAP kinase pathway.
In addition, today's genetic testing can also help assess a patient's risk and develop more targeted treatment plans. Mutations that occur in primary melanoma, especially variations in the CDKN2A and BRAF genes, are considered to be one of the important factors driving the development of the disease.
While our understanding of melanoma continues to improve, the potential for it to spread to unexpected sites remains. Melanoma isn't limited to the skin; it can also appear in places like the mouth and eyes. As a reader, are you ready to learn more about how you can protect yourself from this deadly disease?
