Melanoma

Melanoma is a serious and potentially life-threatening form of skin cancer that develops from the uncontrolled growth of melanocytes, the pigment-producing cells responsible for skin colour.

Melanocytes are normally found in the basal layer of the epidermis, where they produce melanin, a pigment that protects skin cells by absorbing harmful ultraviolet (UV) radiation. While non-cancerous melanocyte growth can result in moles or freckles, malignant transformation of these cells leads to melanoma.

The development of melanoma typically begins when melanocytic stem cells undergo genetic changes, causing abnormal and uncontrolled proliferation.

Melanoma can occur in adults of any age and, though rare, may also develop in children. Several risk factors increase susceptibility, including advancing age, a family history of melanoma, Parkinson's disease, numerous or irregular moles (naevi), and fair skin that burns easily. While people with light and dark skin have a similar number of melanocytes, darker skin contains more active melanin, which offers greater natural protection from UV damage.

Melanoma can appear anywhere on the body, even on areas not commonly exposed to sunlight. Although primarily considered a skin cancer, melanoma can also develop in the eyes, mouth, or even the brain in advanced or rare cases.

Suspicious lesions often resemble unusual moles or freckles that differ in colour, shape, or size. Melanoma may present as brown, black, red, tan, or gray patches. During the horizontal growth phase, lesions are flat, while in the vertical growth phase, they become raised or thickened. Some melanomas may also cause itching, tenderness, or bleeding.

Dermatologists often screen for melanoma using the ABCDE rule or the Glasgow 7-Point Checklist.

• The ABCDE rule evaluates: A - Asymmetry, B - Irregular border, C - Colour variation, D - Diameter greater than 6 mm, and E - Evolving shape, colour, or size.
• The Glasgow checklist classifies features as major or minor. Major criteria include change in size, irregular shape, and irregular colour; minor criteria include inflammation, diameter greater than 7 mm, oozing, and altered sensation.

Diagnosis is typically confirmed using a dermatoscope and skin biopsy, with microscopic analysis by a pathologist to verify melanoma presence and stage.

Melanomas are categorised by their appearance, behaviour, and relationship to sun exposure.

• Early-onset melanoma, often seen in women, is linked with intermittent sun exposure and multiple moles.
• Late-onset melanoma, more common in men, usually appears on sun-exposed areas such as the head and neck and is associated with chronic sun exposure.

Treatment typically involves surgical excision to completely remove the melanoma. In more advanced or widespread cases, surgery may not be sufficient. In these situations, patients may receive immunotherapy, PD-1 inhibitors, or other targeted biologic therapies.

Following treatment, patients undergo regular dermatologic follow-ups to monitor for recurrence. Excision sites are examined carefully, and full-body skin checks are performed. For those with advanced melanoma, periodic blood tests and imaging studies (such as X-rays, CT, MRI, or ultrasound) may be required. Patients with Stage I or II melanoma usually do not need ongoing imaging unless new symptoms arise. Individuals who remain healthy for five years post-treatment are typically discharged from active surveillance.