Current histologic preparation methods for Mohs micrographic surgery

BACKGROUND. Recently Mohs micrographic surgery, which is widely used for the removal of nonmelanoma skin cancers, has been used to remove lentigo maligna with both rush permanent sections and frozen sections. Several investigators have incorporated the use of immunohistochemical techniques to aid in the interpretation of the specimens. OBJECTIVE. To determine the current practices of Mohs surgery laboratories, including the use of immunostains and automation of laboratory processes. METHODS. A total of 108 laboratories responded to a written questionnaire with 13 items about the types of tumors resected, routine stains performed, average number of slides processed per day, and use of automation and immunostains. RESULTS. Forty-nine percent of the laboratories are completely manual and 51% are automated. The Linistainer automated system, which is the predominant one used, decreased processing time by about 30% and provided an estimated 21-30% improved quality. Automation was associated with the number of slides processed. Immunostaining is performed by a limited number of laboratories which use the technique for basal and squamous cell carcinoma, lentigo maligna, and dermatofibrosarcoma protuberans. CONCLUSION. Automation of routine slide preparation with a Linistainer decreased staining variability by providing a consistent environment, and decreased processing time. Most laboratories do not perform immunostaining. The relatively high cost of reagents, lack of a reliable automated process, the additional time to process specimens, and the additional technician and physician time makes the procedure impractical for many laboratories.