The following is a summary of “Permanent section margin concordance after Mohs micrographic surgery with immunohistochemistry for invasive melanoma and melanoma in situ: A retrospective dual-center analysis,” published in the MAY 2023 issue of Young by Dermatology, et al.

There is variability in the use of Mohs micrographic surgery (MMS) for melanoma among dermatologic surgeons. The use of immunohistochemical staining in MMS has been introduced to overcome the challenges associated with slide interpretation. However, the reliability of melanoma antigen recognized by T cells 1 (MART-1), the preferred immunostain for melanoma, has not been compared with permanent section pathology. For a study, researchers sought to evaluate the agreement between MART-1 frozen sections and permanent section pathologic interpretation of melanoma treated with MMS.

A retrospective analysis was conducted at two centers to collect data on agreement and demographics. Chi-square tests were used to compare categorical variables.

Out of 379 permanent sections, 367 were concordant with frozen section pathology, resulting in an overall concordance rate of 96.8%. Cases were categorized into indeterminately concordant and indisputably concordant. 22 (6%) of cases were indeterminately concordant, while 345 (94.0%) of cases were indisputably concordant.

It was the largest study to date evaluating concordance rates of MART-1 frozen sections in Mohs for melanoma. The high concordance rate disputes the need for additional permanent margins when using MART-1 in routine cases.

Source: jaad.org/article/S0190-9622(23)00141-X/fulltext