How should a black pigmented melanoma on the head and chest with pruritus that improves with secondary infection be evaluated and managed?

Immediate Excisional Biopsy Required

Any black pigmented lesion on the head and chest with pruritus requires urgent complete excisional biopsy with 2-5 mm margins to rule out melanoma, regardless of the symptom relief pattern. The mention of "itching relieved by infection" is a red flag that should not delay evaluation, as pruritus is a recognized minor criterion for melanoma 1, 2.

Clinical Evaluation

The lesion meets concerning criteria for melanoma based on established diagnostic frameworks:

• Pruritus (sensory change) is one of the four minor signs in the revised seven-point checklist for melanoma 2
• Black coloration suggests heterogeneous pigmentation (criterion C in ABCDE) 1
• Multiple lesions on head and chest require complete skin examination including scalp and all regional lymph nodes 1

Critical Diagnostic Steps

1. Full skin examination to identify:

   • Additional suspicious pigmented lesions
   • Asymmetry, irregular borders, color variation, diameter >7mm
   • Regional lymphadenopathy and hepatomegaly 1, 3

2. Document lesion characteristics:

   • Size, location, borders, color heterogeneity
   • Presence of inflammation, crusting, or bleeding 1, 2
   • Clinical photographs recommended 3

Biopsy Technique - Critical

Complete excisional biopsy is mandatory - never perform shave, punch, or incisional biopsy 1:

• Full-thickness excision with 2-5 mm clinical margins of normal skin 1, 3
• Include subcutaneous fat cuff 1
• Elliptical incision with long axis parallel to skin lines 1
• Use scalpel only - never laser or electrocautery 1

Rationale: Partial sampling risks misdiagnosis and prevents accurate Breslow thickness measurement, which is essential for staging and prognosis 1.

Common Pitfalls to Avoid

• Do not dismiss pruritus as benign - it appears in 46% of melanomas 2
• Do not delay biopsy based on the unusual "relief with infection" history - this is not a recognized benign pattern
• Do not use dermoscopy alone without biopsy if clinically suspicious 1
• Never biopsy only one lesion if multiple suspicious lesions present - each requires separate evaluation

Histopathology Requirements

The pathology report must include 1:

• Breslow thickness (maximum tumor thickness in millimeters)
• Clark level of invasion
• Presence and extent of ulceration
• Presence and extent of regression
• Mitotic rate
• Margin clearance assessment
• Confirmation of melanocytic origin

Immunohistochemistry (Sox10, S100, Melan-A/MART1, HMB45) should be used if morphologic indicators are unclear 4.

Definitive Management After Diagnosis

If melanoma confirmed:

• Wide local excision with appropriate margins based on Breslow thickness 4:

  • Melanoma in situ: 0.5-1.0 cm margins
  • ≤2 mm thickness: 1 cm margins

  • 2 mm thickness: 2 cm margins

• Sentinel lymph node biopsy indicated for tumors ≥0.8 mm (stage IB or higher) 5, 6

• Staging workup from stage IIB/C: whole-body CT or PET-CT plus brain MRI 5, 7

• BRAF mutation testing mandatory for stage IIC and higher 5, 7

Urgency of Referral

Refer immediately to dermatologist or surgical oncologist with expertise in pigmented lesions 3. These specialists should have systems enabling evaluation within 2 weeks of referral 3. The combination of black pigmentation, pruritus, and multiple sites (head and chest) warrants urgent assessment given melanoma's potential for rapid progression and metastasis.