Ultra-Rapid Diagnostic Tissue Preparation as an Alternative to Frozen Section
Victoria Sujoy, Clifford Blieden, Monica Garcia, Steven E Vernon, Azorides R Morales. University of Miami Miller School of Medicine, Miami, FL; Jackson Memorial Hospital, Miami, FL
Background: Hardening the tissue by freezing, which eliminates the need for fixation, processing and embedding, was introduced as a method for intra-operative pathologic consultation by Louis B Wilson at the Mayo Clinic in 1905. Because of artifacts induced by freezing tissue these intra-operative diagnoses are not uncommonly discordant with that provided by preparation of paraffin embedded blocks from the same frozen tissue (necessary to confirm the pathologic diagnosis rendered during surgery, and also for laboratory accreditation). We sought to determine if modifying conventional histological procedures could allow preparation of H&E sections from paraffin blocks in less than 20 minutes from receipt of tissue in the laboratory.
Design: We developed new tools and grossing procedures to facilitate very thin slicing of fresh tissue, designed a chemical admixture of a ketone, mineral oil and surfactant to use during grossing and microwave-based processing for 8-10 minutes (Sakura's Xpress 50), and modified procedures to shorten paraffin embedding, microtomy, staining and coverslipping to no more than 7 minutes instead of more than 30minutes as is customary. Fresh samples from a variety of different residual tissues and diseases were subjected to this novel tissue preparation method. In addition to H&E, panels of most common histochemical and immunohistochemical stains were done.
Results: The histomorphology of H&E stains obtained with this system is indistinguishable from conventional diagnostic tissue preparation. Moreover, histochemistry and immunohistochemistry results are similar, if not identical, to those obtained with formalin-fixed conventionally processed tissues.
Conclusions: Tissue sections from blocks prepared with this system have morphologic characteristics of similar or identical quality when compared with paraffin blocks prepared by conventional processing. This is a significant improvement over examination of a conventional frozen section, does not suffer from the morphologic artifacts of the latter, precludes the need to process previously frozen tissue and provides intra-operative "permanent section" diagnosis. Moreover, preliminary studies suggest that the preservation of RNA in paraffin blocks obtained with this system is similar to that from fresh frozen tissue.
Tuesday, March 20, 2012 2:30 PM
Platform Session: Section E, Tuesday Afternoon