What is the recommended evaluation and management for a new area of pigmentation on normal skin?

Evaluation and Management of New Flat Pigmented Lesion

For a new area of flat pigmentation on normal skin, urgent referral to a dermatologist is indicated without attempting biopsy in primary care, as this requires expert clinical and dermoscopic evaluation to exclude melanoma, particularly lentigo maligna. 1

Immediate Assessment and Referral Criteria

Urgent specialist referral is mandatory if the pigmented lesion demonstrates any of the following features:

• New pigmented lesion appearing after puberty that is changing in shape, color, or size 1
• Any persistent pigmented lesion where the diagnosis is unclear 1
• Lesions with three or more colors or loss of symmetry 1
• Irregular margins or irregular pigmentation 1
• Symptoms including itching or bleeding 1

The British Journal of Dermatology guidelines emphasize that patients with suspicious lesions must be seen by specialists within 2 weeks of referral. 2

Critical Pitfall: Do Not Biopsy in Primary Care

Lesions suspicious for melanoma should never be removed or biopsied in primary care. 1, 3 This prohibition exists because:

• Punch biopsies and partial sampling techniques make pathological staging impossible, preventing accurate measurement of tumor thickness which is the critical prognostic factor 1, 3
• Clinicopathological correlation by specialists is vital for diagnostic accuracy, which determines prognosis and defines treatment options 1
• Even incisional biopsies have no place in primary care settings 1, 3

Documentation Requirements Before Referral

Document the following clinical features systematically: 1

History:

• Duration of the lesion 1
• Change in size, color, or shape 1
• Associated symptoms (itching, bleeding) 1

Examination:

• Precise anatomic site 1
• Maximum diameter measurement 1
• Elevation status (flat, palpable, nodular) 1
• Description of margins and pigmentation pattern 1

Differential Diagnosis Considerations

For flat pigmented lesions, the primary concern is distinguishing benign conditions from melanoma in situ (particularly lentigo maligna). 2, 4

Benign pigmentation includes:

• Solar lentigines (age spots) - common on sun-exposed areas 5
• Postinflammatory hyperpigmentation 5
• Café au lait macules 5
• Ephelides (freckles) 5

Concerning features suggesting lentigo maligna include: 4

• Asymmetry 4
• Border irregularities 4
• Color heterogeneity 4
• Evolution in size or appearance 4

Role of Dermoscopy

Dermoscopy by trained specialists significantly improves diagnostic accuracy for pigmented lesions. 1, 4 However, this tool requires specialized training and is most appropriately used in specialist settings, not primary care. 1

Special Consideration: Facial Pigmentation

Flat pigmented lesions on the face, particularly in sun-damaged skin, warrant heightened concern for lentigo maligna. 2, 4 Lentigo maligna on facial skin has higher recurrence risk due to a "field effect" where atypical melanocytes extend laterally beyond clinically detectable borders. 2

What Happens After Specialist Referral

If biopsy is required, specialists will perform:

• Complete excisional biopsy with 2-5 mm margins as the gold standard for suspected melanoma 1, 2, 3
• Full-thickness specimen including subcutaneous fat 1, 2
• Incisional biopsy only in highly select circumstances (e.g., large facial lentigo maligna) and only by specialists within skin cancer multidisciplinary teams 1, 2, 4

Patient Education Points

Provide sun protection counseling: 1

• Fair-skinned individuals should limit recreational sun exposure 1
• Avoid sunbed usage, particularly under age 35 years 1
• Use adequate sun protection while maintaining sufficient vitamin D synthesis 1

Teach self-examination for high-risk patients: 1

• Monthly skin self-examination for those with previous melanoma or multiple atypical moles 1
• Recognition of warning signs (changes in size, shape, color) 1