Postfixation of Cryostat Sections Improves Tumor Definition in Mohs Surgery

Abstract

Precise identification and localization of tumor is the key to success in Mohs micrographic surgery. In a pilot study, we demonstrated improvement in tumor definition and staining characteristics after formalin fixation of cryostat sections (postfixation) when compared with unfixed specimens. We further investigated the benefits of postfixation with a series of tissue fixatives and with varying fixation times. In all cases, postfixation was found to be beneficial. No improvement was noted by extending the postfixation time beyond 1 minute.

The Preparation of Frozen Sections for Micrographic Surgery

“…The choice of a fixative is critical for optimal preservation of cellular detail. According to a study conducted by Rustad et al, 14 postfixation of frozen sections can produce sections that are equal to permanent sections obtained with hematoxylin and eosin. Having reviewed his reported results, we decided to compare two different formalin fixatives in a small pilot study.…”

Postfixation Expanded Fixative Study

“…In a survey of university‐associated Mohs surgery units, we found that 15/18 use postfixation (PF), but there is no standardization of the technique. In a previous study we determined, as have other investigators, that PF is beneficial 1–3 . We also determined that fixation time of 1 minute is optimal, and that there are characteristic differences between fixatives.…”

“…We have studied the effect of immersing Mohs cryostat tissue sections in a fixative immediately prior to hematoxylin and eosin staining 1 . In a survey of university‐associated Mohs surgery units, we found that 15/18 use postfixation (PF), but there is no standardization of the technique.…”

“…In theory, such a maneuver might increase hematoxylin uptake in Mohs specimens while maintaining cellular definition. We prospectively studied 20 Mohs patient's specimens, using the methods outlined in our previous study 1 . We compared 10% formalin (as our control) to solutions of fixative cocktail with gradually increasing concentrations of formalin and decreasing concentrations of ethyl alcohol, and to Omnifix with the 1:1 addition of 10% formalin.…”

The influence of post-fixation on visualising vimentin in the retina using immunofluorescence method

“…Post-fixation is a method, which is performed by immersion of sections of fresh frozen tissues into a fixative especially after being sectioned by a cryostat. An increase in staining intensity has been reported after this method [18]. Perfusion fixation with glutaraldehyde and post-fixation with osmium tetroxide is a method used for electron microscopy [21].…”