Is vulvar melanoma more common in Asian women than in Caucasian women?

Vulvar Melanoma: Racial/Ethnic Distribution

Vulvar melanoma is less common in Asian women compared to Caucasian women, with data showing approximately half the incidence rate in Asian populations. 1

Epidemiology and Racial Distribution

The incidence of vulvar melanoma varies significantly across racial and ethnic groups:

• Non-Hispanic Whites: 1.90 per million female population 1
• Hispanics: 1.22 per million female population 1
• Asians and Pacific Islanders: 1.03 per million female population 1
• Blacks: 0.87 per million female population 1
• American-Indians: 0.75 per million female population 1

This creates a white-to-Asian incidence ratio of approximately 1.84:1, demonstrating that vulvar melanoma occurs almost twice as frequently in Caucasian women compared to Asian women.

Key Characteristics of Vulvar Melanoma

Demographics

• Primarily affects older Caucasian women 2
• Mean age of diagnosis is approximately 55 years 3
• Accounts for about 5% of all vulvar neoplasms 2
• Represents approximately 3% of all melanomas in women 3

Anatomical Distribution

• Most commonly located on the labia minora 3
• Can occur anywhere on the vulva
• May present as multifocal disease 4

Clinical Presentation

• Common symptoms include bleeding, pruritus, or a mass in the groin 3
• Often presents as pigmented lesions that may be confused with benign conditions

Etiology and Risk Factors

Unlike cutaneous melanoma, vulvar melanoma shows:

• No association with sun exposure: Incidence does not increase with proximity to the equator 1
• Different racial distribution pattern: The white-to-black incidence ratio for vulvar melanoma (3.14:1) is much lower than that of cutaneous melanoma (13:1-17:1) 1
• Potential risk factors include:
  • Chronic inflammatory disease
  • Genetic susceptibility
  • Irritant agents
  • Viral infections 4

Diagnostic Approach

Diagnosis requires:

• Full-thickness biopsy of suspicious pigmented vulvar lesions 5
• Dermoscopy can aid in differential diagnosis 4
• Molecular profiling often reveals KIT mutations, with BRAF and NRAS mutations also common 2

Treatment Considerations

• Primary treatment is surgical excision 2
• Radical local excision with appropriate margins based on tumor thickness:
  • 1-cm skin margins for melanomas <1 mm thick
  • 2-cm margins for melanomas 1-4 mm thick 5
• Deep margins should be at least 1-2 cm 5
• Lymph node evaluation for patients at increased risk of metastasis

Clinical Implications

The lower incidence of vulvar melanoma in Asian women compared to Caucasian women suggests potential biological or genetic protective factors. However, the racial disparity is much less pronounced than in cutaneous melanoma, suggesting that the microenvironment of mucosal tissues may play a more significant role than racial pigmentation differences 1.

Pitfalls to Avoid

• Delayed diagnosis: Thorough inspection of the vulva during gynecological examinations is essential for early detection
• Misdiagnosis: Vulvar melanoma can be mistaken for other pigmented lesions such as seborrheic keratosis, nevocellular nevus, or lentigo 3
• Inadequate surveillance: Due to higher recurrence rates and potential multifocality, close follow-up is necessary 4

Understanding these racial differences in vulvar melanoma incidence can help guide clinical suspicion and improve early detection efforts, particularly in populations at higher risk.