melanoma

Melanoma is a malignant tumor that originates from melanocytes, the pigment-producing cells in the skin. Although it accounts for a minority of skin cancers, it is the most lethal form due to its tendency to spread early. Melanoma can arise on the skin but also in the eye (uveal melanoma) and other mucosal sites. Risk factors include ultraviolet light exposure, especially intense intermittent sun exposure and sunburns, fair skin, a family history, numerous or atypical moles, and certain genetic changes.

Early detection is based on the appearance of the lesion. Common warning signs are described by the ABCDE criteria: Asymmetry, Border irregularity, Color variation, Diameter larger than 6 mm, Evolving. Diagnosis requires biopsy with histopathology. Staging uses tumor thickness (Breslow depth), ulceration, and spread to lymph nodes or distant sites, classified by the AJCC system.

Treatment depends on stage. For localized tumors, surgical excision with appropriate margins is standard. Sentinel lymph node biopsy may be performed for tumors above a certain thickness to assess regional spread. Adjuvant therapy with immunotherapy or targeted therapy is used in high-risk or unresectable cases. Advanced disease may be treated with immune checkpoint inhibitors, BRAF/MEK inhibitors for tumors with BRAF mutations, radiotherapy for palliation, and, less often, chemotherapy.

Prognosis varies by stage. Localized melanoma without ulceration has the best outlook, while regional and distant metastases carry progressively higher risk of mortality. Five-year survival improves with early detection and complete surgical removal; advanced disease has substantially poorer prognosis.

Prevention focuses on reducing ultraviolet exposure and monitoring the skin. Protective measures include sun protection, avoidance of tanning beds, regular skin checks by individuals and clinicians, and prompt biopsy of suspicious lesions. Genetic testing may be offered in families with known melanoma risk.