Nail Unit Melanoma In Situ Treated With Mohs Micrographic Surgery

BACKGROUND Mohs micrographic surgery (MMS) is under used in the treatment of nail unit melanoma in situ (MIS), with limited studies in the literature. OBJECTIVE Report clinical outcomes for nail unit MIS using MMS with melanoma antigen recognized by T cells-1 (MART-1) immunostaining. METHODS A retrospective observational study at a single academic institution of patients with a diagnosis of nail unit MIS treated with MMS with MART-1 immunostaining from January 1, 2006, to December 30, 2016. The primary outcome measure was the recurrence rate after MMS. RESULTS Fourteen patients were identified. With an average follow-up of 6.0 years (71.6 months; range = 5-139 months), 1 patient developed recurrence 6.6 years after undergoing initial MMS, requiring amputation with no further treatment or recurrence thereafter. CONCLUSION Mohs micrographic surgery for nail unit MIS offers a high cure rate similar to other surgical modalities and can reduce the need for digital amputation. The evolution of the Mohs technique over time, namely, using MART-1 immunostaining, has led to improvement in treatment outcomes. Performing complete nail unit excision with nail plate remaining intact attached to the nail bed may also contribute to improved outcomes. Further refinement in technique and more data are necessary to continue to advance this treatment.