Xylene-free staining: Is it possible and practical?

Abstract

Good paraffin sections are key to correct histopathological diagnosis. Xylene is hazardous to health, expensive, and difficult to dispose. Various substitutes have been tried without success. We aimed to examine if 1.7% dishwasher soap (DWS) aqueous solution and refined mineral oil (RMO) for deparaffinization can replace xylene. Fifty tissue blocks consisting of benign and malignant lesions were processed using xylene (A), 1.7% DWS (B), and RMO (C). Each section was evaluated, scored as 0 (inadequate) and 1 (adequate) by two independent pathologists who were blinded to agent used. Following criteria were considered: nuclear staining, cytoplasmic staining, clarity, crispness, and uniformity. Total score of <2 was graded as inadequate for diagnosis and 3-5 as adequate. Statistical analysis was done using the SPSS software by applying chi-square test. Among three methods, B had the best scores in adequacy for cytoplasmic staining (P = 0.001), clarity (P = 0.004), and crispness (P = 0.003). About 1.7% DWS and RMO were found to be effective methods for deparaffinization and can replace xylene.