Melanoma
Melanoma is a malignant tumor of melanocytes recognized by the ABCDE criteria (asymmetry, border irregularity, color variation, diameter greater than 6 mm, evolving) and confirmed by complete excisional biopsy that captures full lesion thickness. Treatment starts with wide local excision sized to the Breslow tumor depth, adds sentinel lymph node biopsy for deeper lesions, and escalates to BRAF/MEK-targeted therapy or checkpoint immunotherapy for metastatic disease.
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What this article covers
- Overview
Melanocyte malignancy: melanoma is a malignant tumor arising from melanocytes, the pigment-producing cells of the skin, and it is the skin cancer that carries the highest risk of death.
- Epidemiology
Rising clinical importance: melanoma is discussed as a board-favorite malignancy precisely because it is common enough to be tested and dangerous enough that missing it has consequences.
- Risk factors
Ultraviolet (UV) exposure: UV sunlight and a history of sunburns are the leading environmental risk factors.
- Pathophysiology
Radial versus vertical growth: melanoma growth direction determines behavior; a melanoma that spreads outward (radial growth) buys time before it threatens deeper structures, while one that grows…
- Clinical features
ABCDE criteria establish the diagnostic pattern: Asymmetry, Border irregularities, Color variation, Diameter greater than 6 mm, and Evolving change together define the lesion that must be biopsied; a…
- Differential diagnosis
Solar lentigo: uniformly tan and stable in color, unlike the multiple shades of brown and slow enlargement seen in lentigo maligna melanoma.
- Diagnosis
Clinical pearl. The single feature that most reliably breaks a "harmless sun spot" read is more than one shade of brown in an enlarging lesion; color variegation, not size alone, is what should trigger biopsy.
- Management
First step, complete excisional biopsy to diagnose and stage: as above, before any definitive treatment is planned, because the entire management pathway is driven by the measured tumor depth.
- Complications
Nodal metastasis: the primary route of early spread, assessed by sentinel lymph node biopsy in deeper lesions.
- Prognosis
Breslow thickness is the dominant prognostic factor: deeper tumors carry worse prognosis; this single measurement is the strongest predictor available.
- Prevention
Sun protection to reduce UV exposure: because UV sunlight and sunburns are leading risk factors, minimizing UV exposure and sunburn is the primary modifiable prevention strategy supported by the risk-factor evidence.
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