Limited role for histopathological examination of re-excision specimens of completely excised melanomas

The Dutch melanoma guideline advises to examine one central block of the re-excision scar in case of a complete primary excision. To increase the evidence for this recommendation, we re-evaluated how often residual melanoma was found in re-excision specimens of a large series of completely excised melanomas. Of 1,209 Dutch melanoma cases, pathology reports of primary excisions were reviewed. Presence of melanoma in the margins was scored. All melanomas with a complete primary excision were included and pathology reports of re-excisions were reviewed. Presence of residual melanoma in the re-excision specimen and the number of blocks were scored. Slides of re-excision specimens containing residual melanoma were reviewed. Eventually, in four out of 812 melanomas (0.5 %) with a complete primary excision, residual melanoma was found in the re-excision specimen. The free margins of the primary melanomas in these cases ranged from 0.5-3.5 mm. In one case, the margin for melanoma in situ was 0.2 mm. In <1 % of initially completely excised melanomas, residual melanoma was found in the re-excision specimen. Histopathological examination of these re-excision specimens may not be cost-efficient. Our findings even imply that a re-excision could safely be omitted in selected cases of completely excised melanomas.