Should a suspected melanoma be biopsied?

From the Guidelines

Yes, a suspected melanoma should be biopsied. When a skin lesion shows concerning features such as asymmetry, irregular borders, color variations, diameter greater than 6mm, or evolution in appearance (the ABCDE criteria), a biopsy is essential for definitive diagnosis. The preferred method is an excisional biopsy with 1-3mm margins that removes the entire lesion and extends to the subcutaneous fat, as recommended by the guidelines of care for the management of primary cutaneous melanoma 1.

Key Considerations

• If the lesion is large or in a cosmetically sensitive area, an incisional or punch biopsy targeting the most suspicious area may be performed instead, as suggested by the revised U.K. guidelines for the management of cutaneous melanoma 2010 1.
• The biopsy specimen should be sent for histopathological examination by a dermatopathologist, including information on the type of melanoma, actinic damage, maximum vertical thickness in millimeters, information on mitotic rate, presence of ulceration, presence and extent of regression, and clearance of the surgical margins, as outlined in the ESMO clinical practice guidelines for diagnosis, treatment, and follow-up of cutaneous melanoma 1.
• Early diagnosis through biopsy is vital as melanoma treatment outcomes are highly dependent on the stage at diagnosis, with early-stage melanomas having much better prognosis, and delaying biopsy of suspicious lesions can allow potential melanomas to invade deeper and potentially metastasize, significantly worsening outcomes.

Special Cases

• For suspicious subungual lesions, the nail plate should be sufficiently removed to expose the underlying lesion, and an excisional or incisional biopsy performed depending on the size of the lesion, as recommended by the guidelines of care for the management of primary cutaneous melanoma 1.
• Biopsies of possible subungual melanomas should be carried out by surgeons regularly doing so, and the nail should be removed sufficiently for the nail matrix to be adequately sampled, as suggested by the revised U.K. guidelines for the management of cutaneous melanoma 2010 1.

From the Research

Biopsy for Suspected Melanoma

• A suspected melanoma should be biopsied to confirm the diagnosis and assess the Breslow thickness, which is crucial for staging, treatment consideration, and prognosis 2.
• The U.S. Preventive Services Task Force recommends counseling with patient education on minimizing early ultraviolet radiation exposure, and tools such as the ABCDE mnemonic, ugly duckling sign, and dermoscopy can aid in the diagnosis of cutaneous malignant melanoma and the decision to biopsy 2.
• Any suspicious pigmented lesion should be biopsied, and biopsy with a deep scoop shave, saucerization, punch biopsy, or full-thickness excision is preferred to ensure the entire lesion is removed to obtain an accurate measurement of Breslow depth 2.

Types of Biopsy

• Excision biopsy is the gold standard for melanoma diagnosis, as it allows for the removal of the entire lesion and accurate assessment of the Breslow thickness 3, 4.
• Incisional biopsy is acceptable only for extensive facial lentigo maligna or acral melanoma, and punch, shave, and other types of biopsies are not recommended as they do not allow for pathological staging 3.
• Shave biopsy is the most frequent method of diagnosis of cutaneous melanoma, but it may underestimate the true T-stage, and recommendations for excision margin or sentinel lymph node biopsy may change based on the initial biopsy type 5.

Importance of Accurate Biopsy

• Accurate biopsy is crucial for the diagnosis and treatment of melanoma, as it allows for the assessment of the Breslow thickness and the determination of the appropriate treatment plan 2, 4.
• Inaccurate biopsy can lead to delayed diagnosis, subsequent definitive treatment, and adverse patient outcomes 3.
• Incisional biopsies are not associated with an unfavorable prognosis for melanoma patients, but complete excision of primary melanoma is still the recommended standard of care and is a precondition for accurate histopathologic diagnosis 6.