Skin mapping with punch biopsies for defining margins in melanoma: when you don't know how far to go.

BACKGROUND: Wide local excision of primary cutaneous melanoma usually provides clear margins and excellent local control. Nonclassical presentations of cutaneous melanoma, however, can challenge this treatment algorithm. Specifically, persistent melanoma-in-situ (MIS) at the margin not suspected clinically makes planning definitive wide local excision more difficult. We hypothesized that the use of punch biopsies as a mapping tool would allow us to obtain clear margins in these challenging cases.
METHODS: Punch biopsies were performed at sites 1 to 2 cm from prior positive margins. Subsequent wide local excision was planned, including all punch biopsy sites with positive findings: atypical melanocytic hyperplasia, MIS, or invasive melanoma. The management of three patients was documented prospectively. Standard surgical techniques were used independent of an experimental protocol. Medical records were reviewed, and data were summarized under institutional review board protocol HIC 10803.
RESULTS: The results of punch biopsies identified invasive melanoma, MIS, or atypical melanocytic hyperplasia in all three patients with MIS at the margins. All three mapping procedures were well tolerated and resulted in resection with negative margins in a single definitive resection.
CONCLUSION: Melanoma mapping with punch biopsy technique allows for definitive excision in cases when disease persists at the margins of the reexcision or in cases with unclear clinical examinations.