IMMUNOHISTOCHEMICAL TECHNIQUES IN MOHS MICROGRAPHIC SURGERY - THEIR POTENTIAL USE IN THE DETECTION OF NEOPLASTIC-CELLS MASKED BY INFLAMMATION

Background: Histopathologic evaluation of tissue obtained from Mohs micrographic surgery is the key step in obtaining complete tumor removal. Residual undetected tumor may result in recurrence. Objective: In circumstances in which the histopathologic interpretation is difficult, we assessed the potential use of immunohistochemical techniques to detect tumor in Mohs micrographic surgical specimens. Methods: A rapid immunoperoxidase technique with monoclonal anticytokeratin antibodies was performed on Mohs frozen sections. Cases selected included morpheaform basal cell carcinomas, perineural tumors, and sections with dense inflammation without apparent tumor. Results: Four cases are described as examples that highlight the potential usefulness of immunostaining of Mohs tissue sections. Anticytokeratin antibodies helped to confirm free tumor margins, thus avoiding the unnecessary sacrifice of normal tissue, and to delineate tumor not identified in hematoxylin and eosin frozen sections. Conclusion: Immunohistochemical staining of Mohs micrographic surgical specimens with anticytokeratin antibodies is particularly useful when dense inflammatory infiltrate is present, because the latter may obscure any residual tumor. Application of this technique to difficult cases may prevent tumor recurrences or unnecessary excision of normal tissue.