Last updated: November 29, 2023

Summarytoggle arrow icon

Melanoma, a malignancy arising from melanocytes, is the most common cause of skin cancer-related death. Risk factors include UV radiation exposure (especially in individuals with light skin), dysplastic nevi, a family history of melanoma, and immunosuppression. Melanoma is most commonly cutaneous in origin, but may also arise in mucosal surfaces and in the uvea. There are four main histological subtypes of melanoma. Superficial spreading melanoma is the most common, while nodular melanoma tends to grow rapidly in depth and has the worst prognosis of all the subtypes. Clinical features concerning for melanoma include asymmetry, border irregularity, color variegation, diameter > 6 mm, and evolving size, shape, and/or color over time (i.e., the ABCDE criteria). Full-thickness excisional biopsy of skin lesions is the best diagnostic test for melanoma and should be performed immediately in all patients with suspicious lesions. Additional diagnostic and staging tests (e.g., sentinel lymph node biopsy and/or imaging) may be indicated in certain patients. Tumor thickness is a key prognostic factor. Treatment is primarily surgical and includes wide excision of the lesion with surgical margins determined by the tumor thickness. Systemic drug therapy (e.g., with immune checkpoint inhibitors, BRAF inhibitors, and MEK inhibitors) or radiation therapy may be indicated in patients with metastatic or unresectable disease.

Epidemiologytoggle arrow icon

  • Most common cause of skin cancer-related death [1][2]
  • Incidence is higher among individuals who are: [3]
    • Non-Hispanic White
    • Male
    • ≥ 75 years of age

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Risk factors for cutaneous melanoma [4][5]

Clinical featurestoggle arrow icon

The following are general features of cutaneous melanoma. See “Types of melanoma” for specific features of various melanoma subtypes.

ABCDE criteria [11]

The following skin lesion characteristics are concerning for melanoma:

  • A = Asymmetry
  • B = Border (irregular border with indistinct margins)
  • C = Color (variegated pigmentation within the same lesion)
  • D = Diameter > 6 mm
  • E = Evolving (a lesion that changes in size, shape, or color over time)

Other signs and symptoms [11][12]

Subtypes and variantstoggle arrow icon

By site of origin [13][14]

By histology [11][15]

Both cutaneous melanomas and mucosal melanomas may be categorized by these subtypes.

Histological subtypes of melanoma [11][15]
Epidemiology Typical sites Clinical appearance Growth

Superficial spreading melanoma

  • ∼ 70% of all melanomas
  • Back, chest, head, neck (in men)
  • Legs (in women)
  • Flat irregular lesion with irregular borders
  • Sometimes with nodular segments
  • Variable pigmentation
  • Relatively slow horizontal growth

Nodular melanoma

  • 15–30% of all melanomas
  • Fast growth in depth [16]

Lentigo maligna melanoma

  • < 10% of all melanomas [4]
  • Often arises from lentigo maligna in older adults
  • Sun-exposed skin areas (esp. the face and forearms)
  • Development of the following within a lentigo maligna lesion:
    • Papules or nodules
    • Variegated colors of red, blue, and white
  • Relatively slow horizontal growth

Acral lentiginous melanoma

  • < 5% of all melanomas
  • Most common melanoma in dark-skinned and Asian individuals
  • Irregularly shaped macule with variegated colors including black, brown, and blue
  • Slow horizontal growth

Nodular melanomas have a rapid vertical growth rate and may be better identified by use of the EFG criteria (Elevation, Firmness to touch, Growth) than the more general ABCDE criteria. [17]

Amelanotic melanoma [15]

  • Any of the other histological subtypes may present; , less commonly, as amelanotic melanoma.
  • Melanocytes in the lesion produce little to no pigment, causing the color to range from skin-colored to bright pink or red. [18]
  • Diagnosis typically requires histological confirmation.

Genitourinary melanoma (GU melanoma) [19]


  • Rare (< 5%)
  • Approx. 45% of all mucosal melanomas
  • Most commonly affects female individuals (approx. 90%)
  • Cause remains unknown.
  • Expression of cell biomarkers such as PD-1 and PD-L1 in vulvar melanoma is significantly higher than in cutaneous melanomas.
  • Prognosis is generally poor.

Types of GU melanoma

Overview of GU melanoma types
Characteristics Female genital melanoma Male genital melanoma Urological mucosal melanoma
  • Rare: ∼ 1% of all melanomas, 5% of vaginal malignancies [20][21]
  • >
  • Peak age of onset: 7th decade
  • Peak age of onset: 6th decade
  • Vulvar melanoma
  • Vaginal melanoma
  • Renal melanoma
  • Ureteral melanoma
  • Bladder melanoma
  • Urethral melanoma
Clinical features
  • Clinical presentation and histopathological confirmation
  • Surgical resection with an adequate margin

Subungual melanoma [22][23]

  • Rare subtype of cutaneous acral lentiginous melanoma that develops within the nail unit
  • Commonly manifests as melanonychia (a brown to black longitudinal band), with additional features suggestive of malignancy:
    • Extension of pigmentation proximally or laterally to involve the nail folds (Hutchinson sign of the nail)
    • Width of pigmentation > 3 mm with triangular shape (distal tapering)
    • Nail dystrophy, fissuring, or splitting [15]
    • Involvement of a single nail

Diagnosticstoggle arrow icon

Approach [11][24][25]

Skin biopsy [24][25]

  • Full-thickness excisional biopsy: preferred method for all suspicious lesions [25]
  • Incisional (partial) biopsy
    • May be performed for certain lesions (e.g., on the face or digits, or that are large in size)
    • If the full thickness of the lesion is not captured on biopsy, accurate melanoma staging may not be possible.

Excisional biopsy of suspected melanoma should encompass the full depth of the lesion, as lesion depth is important for staging and prognostic purposes. [25]

Clearly document the lesion dimensions, size of surgical margins, and type of biopsy to guide subsequent management. [11][25]

Pathologytoggle arrow icon

Stagingtoggle arrow icon

Determination of stage

Sentinel lymph node biopsy (SLNB) [24][25]

SLNB is recommended in certain patients, after careful discussion of risks and benefits and with the involvement of surgical oncology.

SLNB is not indicated in patients with cutaneous melanoma < 0.8 mm in depth without ulceration or other concerning features. [25]

Additional studies [25]

LDH is not used to evaluate for metastasis, but may be used as a prognostic indicator in patients with stage IV melanoma. [25]

AJCC staging of cutaneous melanoma

Melanoma is staged using the American Joint Committee for Cancer (AJCC) TNM staging system.

AJCC staging of cutaneous melanoma (2018) [25][28]
Tumor characteristics (T) Regional spread (N) Distant metastasis (M)
Stage 0 melanoma
  • None
  • None
Stage I melanoma
Stage II melanoma
Stage III melanoma
  • Present
Stage IV melanoma
  • May or may not be present
  • Present

Differential diagnosestoggle arrow icon

Benign skin lesions [29]

These may include:

Benign skin lesions can resemble melanomas; biopsy should be performed to rule out melanoma. [30]

Precancerous skin lesions [30]

These may include:

Other skin cancers [15][30]

Overview of common skin cancers [15][30]
Cutaneous melanoma [11][12] Cutaneous squamous cell carcinoma Basal cell carcinoma (BCC) [31]
  • Brown, black (variable pigmentation)
  • Red
  • Pink or red
  • Pigmented BCCs may be brown, black, or blue.
  • Irregular macule, nodule, or patch
  • Usually sun-exposed areas, e.g.:
    • Forearms
    • Back of hands
    • Head and neck, including ears and lower lip
  • Usually sun-exposed areas; most commonly on the head and neck
Other characteristic features

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Approach [9][24][25]

Wide local excision [9][24][25]

Recommended surgical margins for invasive melanoma resection
Breslow depth Surgical margin

Tumor in situ

  • 0.5–1 cm

≤ 1 mm

  • 1 cm

> 1 mm and ≤ 2 mm

  • 1–2 cm

> 2 mm

  • 2 cm

First-line treatment for melanoma is prompt, complete excision of the tumor. [11][25]

Medical therapy for melanoma [9][24][25][34]

Systemic drug therapy

Other therapies

Follow-up care for melanoma [25]

Dermatologic examinations

  • All patients should have lifelong follow-up with a dermatologist, focusing on:
    • Monitoring for melanoma recurrence
    • Screening for new primary melanoma
  • Tailor frequency of visits to disease stage, e.g., as shown in the table below.
Follow-up dermatologic examination schedule for cutaneous melanoma [25]
Disease stage Recommendation
Stage 0 melanoma
  • Every 6–12 months for 1–2 years
  • Then annually
Stage I melanoma and stage IIA melanoma
  • Every 6–12 months for 2–5 years
  • Then annually
Stage IIB melanoma and higher
  • Every 3–6 months for 2 years
  • Then every 6 months for 3–5 years
  • Then annually

Surveillance imaging

Suveillance imaging to detect occult metastasis may be performed in select patients for up to 3–5 years after diagnosis.

Patients with positive SLNB (i.e., stage III melanoma) are now typically managed with lymph node ultrasound surveillance instead of complete lymph node dissection. [24][25]

Complicationstoggle arrow icon

Metastatic disease [36]

We list the most important complications. The selection is not exhaustive.

Prognosistoggle arrow icon

  • Negative prognostic factors
    • Epidemiological features: male sex
    • Clinical features: type , localization , and presence of ulcerations
    • Melanoma has a significant risk of metastasis, which is associated with a poorer prognosis.
    • Tumor thickness, as determined from the Breslow thickness, is the most important prognostic factor.
    • Regression

Preventiontoggle arrow icon

Primary prevention [7][27]

  • Provide advice on the importance of minimizing UV radiation exposure to reduce the risk of melanoma, including:
  • The USPSTF specifically recommends providing advice to individuals who have light skin and are: [7]


  • Asymptomatic individuals with no prior skin cancer: The USPSTF has found insufficient evidence to recommend for or against screening. [7][38]
  • Adults with risk factors for cutaneous melanoma: Clinicians may consider performing periodic total body skin examinations. [27][39]

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Referencestoggle arrow icon

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