Dual Immunostaining With SOX10 and AE1/AE3 to Confirm Perineural Invasion on Mohs Sections.

Perineural invasion (PNI) is associated with high risk keratinocyte carcinomas. Identification of PNI during Mohs surgery is important for staging and post-adjuvant treatment decisions but can be challenging. To confirm or exclude PNI suspected on hematoxylin and eosin sections, we performed immunohistochemical double staining on Mohs frozen sections. Neural marker SOX10 and pan-cytokeratin marker AE1/AE3 were combined in a simultaneous assay using species-specific (mouse and rabbit) antibodies and horseradish peroxidase and alkaline phosphatase detection systems. Of 23 Mohs cases with suspected PNI, 18 were confirmed to have definitive nerve involvement by tumor using double staining. Double staining frozen tissue is feasible and can be beneficial for real time confirmation of PNI during Mohs. J Drugs Dermatol. 2019;18(3):262-264.