Sampling of wide local excision specimens in cutaneous malignant melanoma.

Background: Wide local excisions (WLEs) are frequently undertaken in the management of cutaneous melanoma; however, there is a considerable variability in their macroscopic sampling. The aim of our study was to establish evidence-based guidelines for the macroscopic handling of these specimens with a subsequent review of the impact on our service.

Methods: The study group of 128 cases with initial biopsy and subsequent WLE in our institution in 2010 were identified by a computer-generated search. From analysis of this group, guidelines for macroscopic sampling were derived with a repeat search performed in 2012.

Results: Residual melanoma was detected only in those cases in which the original specimen had clear margins of ≤1 mm or with a pigmented lesion. A 32% increase in case numbers was noted over this period with a reduction of 6.2% in block numbers. Average block numbers per case were reduced by 2.3 (30.7%).

Conclusions: We have shown that for WLE specimens with no evidence of a macroscopic lesion and clear margins on original biopsy, little is to be gained from extensive sampling. In these cases we recommend a maximum of 3 blocks per case. Reduction in sampling based on this evidence would result in saving valuable laboratory resources.