Guidelines for Melanoma Biopsy, Staging, and Surgical Margins

Conclusions

• For suspected melanoma, the preferred biopsy is an excisional or complete biopsy with narrow 1 to 3 mm margins and sufficient depth to avoid transecting the invasive component.
• Saucerization or deep shave removal is often an acceptable and commonly preferred way to accomplish complete sampling when it removes the full clinical lesion and yields an accurate Breslow depth.
• Partial biopsies can under-stage melanoma and miss the true Breslow thickness, so repeat biopsy or microstaging is warranted when the initial specimen does not provide confident diagnostic or treatment-planning information.
• When partial biopsy is unavoidable, it should be reserved for select situations such as large lentigo maligna, acral/subungual lesions, bulky tumors, or low-suspicion facial lesions where complete excision is impractical.
• Biopsy technique does not appear to increase metastasis, sentinel node positivity, recurrence, or survival risk based on available studies and meta-analyses.
• Elliptical excisions on extremities should be oriented longitudinally to preserve lymphatic drainage and support accurate future sentinel node mapping.
• Biopsy-site photography and standardized anatomic labeling improve correct site identification and reduce wrong-site surgery risk.
• For melanoma surgery, recommended peripheral margins are based on Breslow depth, with narrower margins for in situ and thin lesions and 2 cm for thicker invasive melanoma.
• Clinical margins, not histologic margins, are the basis for surgical margin recommendations, although very narrow histologic clearance may justify re-excision.
• Sentinel lymph node biopsy should be performed before or at the same operation as wide excision when indicated, because prior wide surgery can disrupt lymphatic mapping.
• For melanoma on digits, management requires specialized expertise, and digit-sparing approaches may be reasonable in selected low-risk cases but remain under study.