Histomorphological Assessment of Formalin versus Nonformalin Fixatives in Diagnostic Surgical Pathology

Introduction  Fixation is the critical step in the preservation of tissues in diagnostic pathology. The formalin is an economical and excellent fixative with the inherent property of adequate fixation. The well-established side effects of formalin include mucosal irritation, upper respiratory diseases, and corrosive injury to the gastrointestinal tract. In addition, substantial evidence exists regarding the potential role of formaldehyde as a human carcinogen. The carcinogenic and toxic effects of formalin encourage searching for alternative fixatives for tissue fixation. However, "the formalin dogma" has severely hampered the search for alternative fixatives for many years. Material and Methods  Ninety tissues of liver and skeletal muscle obtained during autopsies were immersed in adequate amounts of the following fixatives: formalin (10%), methyl alcohol (70%), and acetone (100%). The comparison among the three was made based on time for fixation, preservation of tissue architecture, cell borders, cytoplasm, nuclear contours, chromatin texture, and uniformity of staining. Results  The tissue preserved in formalin undergoes rapid fixation compared with alcohol and acetone. The tissue architecture, cell border characteristics of alcohol and acetone was found satisfactory compared with formalin. The cytoplasm and nuclear contour were superior with the formalin. The chromatin texture and uniformity of staining were similar with all the three fixatives. Conclusion  The formalin is considered superior to most of the parameters, whereas both methyl alcohol and acetone showed nearly equivalent scores. Hence, owing to the potential human health hazards and carcinogenicity of formalin, no rational reasons hamper the complete substitution of formalin with alternative fixatives such as alcohol and acetone in diagnostic pathology and medical research.