melanome

Melanome, or melanoma, is a malignant tumor that arises from melanocytes, the pigment-producing cells of the skin and, less commonly, mucous membranes or eye tissue. It most often affects the skin but can develop anywhere melanocytes are present.

Risk factors include ultraviolet radiation exposure from sun or tanning devices, history of severe sunburns, fair skin, light hair or eyes, a high number of moles or dysplastic nevi, and certain inherited genetic mutations (for example CDKN2A, BRAF, NRAS, KIT). The disease often evolves from existing nevi, though de novo tumors also occur.

clinically, melanome typically presents as a new or changing pigmented lesion. Warning features include asymmetry, irregular or poorly defined borders, color variation, diameter larger than about 6 mm, and evolving size or shape. Symptoms such as itch, ulceration, or bleeding may occur. Diagnosis relies on a full-thickness skin biopsy with adequate margins for histopathologic examination. Staging uses the AJCC system, with factors such as Breslow thickness (depth of invasion), ulceration, mitotic rate, and lymph node or distant metastasis guiding prognosis and treatment. Sentinel lymph node biopsy is common for tumors of certain thickness or with adverse features. Imaging and laboratory tests help detect metastasis when indicated.

Treatment is primarily surgical, aiming for complete excision with appropriate margins. Additional therapies include sentinel lymph node biopsy, adjuvant immunotherapy (for example checkpoint inhibitors like pembrolizumab or nivolumab) or targeted therapy for tumors with BRAF mutations (e.g., dabrafenib with trametinib). Radiotherapy and systemic therapies may be used for metastatic disease or palliation, and participation in clinical trials is common.

Prevention focuses on sun protection, avoiding tanning beds, and regular skin examinations by individuals and health professionals. Outcomes depend strongly on stage at diagnosis and tumor biology.