What is the role of surgery in the treatment of lentigo maligna melanoma?

Updated: Dec 19, 2019
  • Author: Winston W Tan, MD, FACP; Chief Editor: William D James, MD  more...
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Lentigo maligna is treated with definitive surgical therapy. The actual margins of atypia usually extend beyond the clinically apparent margin, so total removal may be difficult. National Comprehensive Cancer Network (NCCN) practice guidelines for melanoma in 2019 are as follows (tumor thickness, recommended clinical margin) [19] :

  • Tumor in situ – Margin size 0.5-1.0 cm
  • Tumor ≤1.0 mm – Margin size 1.0 cm
  • Tumor 1.01-2 mm – Margin size 1-2 cm
  • Tumor 2.01-4 mm – Margin size 2.0 cm
  • Tumor > 4 mm – Margin size at least 2.0 cm

The NCCN notes that for large melanoma in situ of the lentigo maligna type, surgical margins wider than 0.5 cm may be necessary. [19] In a study by Kunishige and colleagues in 1120 patients with melanoma in situ treated with Mohs surgery, 6-mm margins removed 86% of melanomas while 9-mm margins removed 99%. [21]

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