Frozen Sections from Bouin-Fixed Material in Histopathology

Abstract

It has become almost a dogma that, for obtaining satisfactory frozen sections, fixation of the tissues in formalin is necessary; formalin is exclusively recommended for this purpose in the textbooks of microscopical and pathological technic.¹ It has, however, several important disadvantages, which become the more acutely felt when fixation in more than one fixative is impossible, as happens so often in surgical pathology. When, after the preparation of the frozen sections, embedding in paraffin is necessary, formalin-fixed tissues show a marked shrinkage, especially when rapid embedding methods (e. g. dioxane) are used. This shrinkage can only be prevented by the time-consuming hardening of the blocks in K₂Cr₂O₇. The trichrome stains, the phosphotungstic-hematoxylin stain and the azan method, which are slowly superseding the hematoxylin-eosin and van Gieson stains in histopathology, give only mediocre or inferior results after formalin fixation, unless the sections are refixed.