Tissue preparation for MOHS' frozen sections : a comparison of three techniques

Accurate, efficient frozen section analysis is important for tumor control. A few studies address the technical issues. More are needed, especially as new technologies become available. The objective of this study is to compare the efficiency of three techniques of flattening tissue for microscopically oriented histologic surgery (MOHS): conventional frozen sectioning, Cryocup, and CryoHist. Conventional chuck/heat sink-frozen section preparation were compared with Cryocup and CryoHist to determine the most efficient technique to examine 100% of the surgical margin of 4-cm diameter, full thickness, fresh autopsy cylinders of anterior abdominal skin, which were marked on their deep and peripheral margins. The specimens were frozen sectioned at 5 microm until all the marking dye was gone from the deep surface, and 95% of the perimeter epidermis could be seen. The conventional chuck required an average of 304 micrometers to clear the deep margin and four fifths did not contain 95% of the epidermal margin. The Cryocup required an average of 284 microm to examine the deep margin and 95% of the epidermal margin. The CryoHist required an average of 104 microm to examine the deep margin and 95% of the epidermal border. The new techniques improve the efficiency and presumably the accuracy of tumor margin analysis.