Understanding Malignant Melanoma

Overview of Malignant Melanoma

Malignant melanoma is a type of skin cancer that originates in melanocytes, the skin cells responsible for producing melanin. This cancer typically manifests as a tumor on the outer layer of the skin. Both genetic predisposition and environmental influences contribute to the onset of melanoma, making individuals with a family history of the disease particularly cautious. Prolonged exposure to both natural and artificial ultraviolet rays is a significant risk factor. The incidence of melanoma is on the rise globally, and it is recognized as the most dangerous form of skin cancer. Once deemed rare, melanoma now ranks as the fifth most common cancer in men and the sixth in women in the United States, accounting for approximately 50,000 deaths annually worldwide. While melanoma can affect individuals of all ages, it is most frequently diagnosed in middle-aged individuals. Caucasians, especially those with fair skin, red or blonde hair, light eyes, and numerous moles and freckles, are at a higher risk, being 50% more likely to develop the condition. However, it is essential to note that melanoma can occur in individuals of any ethnicity.

Types of Melanoma

Acral Lentiginous Melanoma

This type typically appears on the hands, feet, fingernails, and toenails, and is most commonly found in individuals with darker skin tones.

Lentigo Malignant Melanoma

These lesions develop in areas frequently exposed to sunlight, making them more prevalent in older adults. They usually present as brown or black spots.

Nodular Melanoma

This aggressive form of melanoma penetrates deeper into the skin and often occurs on the face, chest, and back, making it the most threatening variant.

Superficial Spreading Melanoma

Characterized by outward growth, this is the most common type of melanoma.

Symptoms of Malignant Melanoma

Initially, melanoma may appear as a new mole or an alteration in an existing mole or freckle. These lesions are commonly brown or black but may also exhibit red, pink, grey, blue, or white hues. Within the lesion, various features such as holes, dots, globules, streaks, irregular pigmentation, and blood vessels may be present. The lesions can be flat or raised, typically measuring 2 mm or less, but can grow up to 20-30 mm. In men, melanoma frequently develops on the legs, while in women, it appears on the legs and arms. However, melanoma can also be found on the scalp, face, hands, feet, and toenails in both genders.

ABCDE Criteria

To help identify signs of melanoma, the ABCDE criteria can be utilized:
– Asymmetry: One half of the spot does not match the other.
– Border: The edges are irregular or rough.
– Colour: Variations may include brown, black, red, grey, blue, or white.
– Diameter: The lesion may be as small as 2 mm.
– Evolution: Monitor for changes in size, colour, or shape.

Diagnosis of Malignant Melanoma

Early detection of malignant melanoma is crucial for effective treatment, as the disease can develop over weeks to years. If a lesion appears suspicious, a skin biopsy should be performed promptly, and the tissue should be sent to a pathologist for analysis. When detected early, the survival rate for melanoma is approximately 90%. However, if diagnosed at a later stage, the cancer may spread to the bloodstream and lymphatic system. Healthcare providers may conduct a lymph node biopsy, CT scan, MRI, PET scan, or blood tests to assess the cancer’s spread.

Additional Diagnostic Methods

– ABCDE criteria: Regular self-examinations and evaluations by healthcare providers can aid in early detection.
– Total-body images: These can serve as references for monitoring skin changes and lesions.
– Glasgow 7-point checklist: This diagnostic tool assesses size, shape, and colour of lesions, along with changes in diameter, inflammation, bleeding, and scabbing.
– “Ugly duckling” sign: This concept helps identify lesions that appear different from others on the skin.
– Optical devices: Tools such as dermoscopy and Reflectance Confocal Microscopy are effective in melanoma detection.

Stages of Disease

The progression of melanoma can vary significantly. As the disease advances, lesions may enlarge and change in colour or appearance. Symptoms such as sensitivity, itching, scabbing, or bleeding may also develop.

Treatments for Malignant Melanoma

Surgery is the most common treatment for melanoma. Other treatment options include skin grafting, BRAF inhibitors, immunotherapy, oral medications (such as Vemurafenib and Dabrafenib), targeted therapy, adjuvant therapy, chemotherapy, and radiotherapy.

Prevention

The most effective strategy for preventing melanoma is to minimize exposure to natural and artificial ultraviolet radiation. It is essential to avoid prolonged sun exposure and sunburns, particularly during childhood. Protective measures include wearing sunscreen, hats, and clothing to shield the skin.

References

– Canadian Cancer Society: Melanoma. 2018, http://www.cancer.ca/en/cancer-information/cancer-type/skin-melanoma/melanoma/?region=on. Accessed 26 July 2018.
– Canadian Dermatology Association: Melanoma. 2018, https://dermatology.ca/public-patients/skin/melanoma/. Accessed 26 July 2018.
– Corrie, Pippa, et al. “Management of Melanoma.” British Medical Bulletin. 2014. 111: 149-162. Online.
– Malignant Melanoma. 2018, https://emedicine.medscape.com/article/280245-overview. Accessed 26 July 2018.
– Melanoma of the Skin. 2018, https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024659/, accessed 26 July 2018.
– Rastrelli, Marco, et al. “Melanoma: Epidemiology, Risk Factors, Pathogenesis, Diagnosis and Classification.” 2014. 28: 1005-1012. Online.