Comparative evaluation of staining efficacy of calcofluor white and acridine orange in detecting fungal elements in oral potentially malignant disorders and oral squamous cell carcinoma - A retrospective study.

Background: Candida is an opportunistic fungal pathogen that frequently colonizes the oral mucosa. Depending on multiple etiological factors, Candida can transform from a harmless commensal into a pathogenic organism, leading to the development of oral potentially malignant disorders (OPMDs) and oral cancer. Although various laboratory diagnostic methods for Candida have been developed, there remains a need for more rapid and sensitive diagnostic aids for infections associated with Candida. The present study aimed to compare the efficacy of Calcofluor white and acridine orange fluorescent stains and evaluate the most efficacious stain.

Materials and methods: Two fluorescent stains, calcofluor white and acridine orange, were used to identify Candida elements in formalin-fixed, paraffin-embedded tissue sections of oral potentially malignant disorders (n = 16), including leukoplakia without dysplasia, mild dysplasia, moderate dysplasia, severe dysplasia, oral lichen planus, and oral sub mucous fibrosis as well as oral squamous cell carcinoma (n = 16), encompassing well-differentiated, moderately differentiated, and poorly differentiated grades. All stained slides were examined using a fluorescence microscope equipped with a blue filter at 20× and 40× magnifications. The comparison between the two stains was conducted based on the expression of fungal elements or the grade of Candida within the given sections, staining quality, and cost-effectiveness.

Results: The results of the present study confirmed that both stains produced similar outcomes in terms of the expression of fungal elements within the sections of oral potentially malignant disorders and oral squamous cell carcinoma. Using both stains, all cases were positive (n = 32), with no negative cases reported. Grade I and II Candida was identified in the sections of oral potentially malignant disorders, whereas Grade III and IV Candida were observed within the sections of oral squamous cell carcinoma and sever dysplasia. Calcofluor white stain demonstrated higher efficiency in terms of staining quality and cost-effectiveness.

Conclusion: Calcofluor white stain exhibited better expression of Candida elements in cases of oral potentially malignant disorders and oral cancer in terms of staining efficacy and is also more cost-effective.