Low recurrence rates for in situ and invasive melanomas using Mohs micrographic surgery with melanoma antigen recognized by T cells 1 (MART-1) immunostaining: Tissue processing methodology to optimize pathologic staging and margin assessment

BackgroundVarious methods of tissue processing have been used to treat melanoma with Mohs micrographic surgery (MMS).ObjectiveWe describe a method of treating melanoma with MMS that combines breadloaf frozen sectioning of the central debulking excision with complete peripheral and deep microscopic margin evaluation, allowing detection of upstaging and comprehensive pathologic margin assessment before reconstruction.MethodsWe conducted a retrospective cohort study evaluating for local recurrence and upstaging in 614 invasive or in situ melanomas in 577 patients treated with this MMS tissue processing methodology using frozen sections with melanoma antigen recognized by T cells 1 (MART-1) immunostaining. Follow-up was available in 597 melanomas in 563 patients.ResultsLocal recurrence was identified in 0.34% (2/597) lesions with a mean follow-up time of 1026 days (2.8 years). Upstaging occurred in 34 of 614 lesions (5.5%), of which 97% (33/34) were detected by the Mohs surgeon before reconstruction.LimitationsLimitations include retrospective study, intermediate follow-up time, and that the recurrence status of 39.6% of patients was self-reported.ConclusionTreating melanoma with MMS that combines breadloaf sectioning of the central debulking excision with complete peripheral and deep microscopic margin evaluation permits identification of upstaging and consideration of sentinel lymph node biopsy before definitive reconstruction and achieves low local recurrence rates compared with conventional excision.