Novel 16-minute technique for evaluating melanoma resection margins during Mohs surgery

Immunohistochemistry (IHC) applied to Mohs micrographic surgery (MMS) is time consuming and labor intensive, and the variability of staining quality has prevented its widespread use in clinical practice.

To investigate the readability of immunostains processed by a novel automated 16-minute technique used for evaluation of frozen sections prepared during MMS for melanoma.

A rapid automated instrument that performs MART-1 (melanoma antigen recognized by T cells) immunostains in 16 minutes was used to stain frozen sections and was compared with MART-1 stains of paraffin (permanent) sections, hematoxylin-eosin (H&E) stains of frozen and permanent sections from the positive or negative control specimens of the Mohs layers for melanoma. A total of 480 interpretations from 48 sections (4 types of stains for each specimen, 12 specimens read by 10 interpreters) were analyzed via blinded examination by 5 dermatopathologists and 5 Mohs surgeons at two institutions. A scoring system was used to assess the readability of each slide. Analysis of variance was used for statistical analysis.

In terms of clarity of interpreting melanoma sections, the 16-minute MART-1 IHC of frozen sections is equivalent to the standard MART-1 of permanent sections. The 16-minute MART-1 sections are also significantly easier to interpret than permanent sections stained with H&E for both the dermatopathologists and Mohs surgeons (P < .05).

The study represents data collected from only two institutions in the United States.

The rapid-stained frozen IHC sections are significantly easier to interpret than the "gold standard" permanent sections stained with H&E. This technology facilitates the rapid interpretation of melanoma in frozen sections.