Application Of Modified Calcofluor White Fluorescence Staining In Histopathological Diagnosis Of Subcutaneous Mycosis

Objective:Subcutaneous fungal diseases often need to be diagnosed by histopathological examination,and the traditional staining methods have become increasingly difficult to meet the increasing clinical needs.The purpose of this study was to evaluate the value of modified Calcofluor White(CFW)fluorescence staining in pathological diagnosis of subcutaneous mycoses.Methods:1.From 1987 to 2017,21 cases of subcutaneous fungus admitted to the affiliated hospital of Chengde medical University were selected,including 2cases of head and face infection,14 cases of upper limb infection and 5 cases of lower limb infection.2.Histopathological examination was performed in 21 selected cases.There were 11 cases of sporomycosis,3 cases of coloration spores,1 case of gypsum-like tinea,1 case of Candida and 1 case of Trichoderma,among which 9 cases failed to improve the fungal culture,but the experiment with antifungal drugs was effective.3.The paraffin embedded tissues were tested in parallel.Four 4 ? m sections of each tissue were stained by modified CFW fluorescence staining,HE staining,PAS staining and GMS staining respectively.The modified CFW fluorescence stained sections were examined under(UV)filter,HE staining,PAS staining and GMS staining under ordinary optical microscope.The positive results were determined and the images were collected.4.SPSS 19.0 software was used to compare the positive rate of four staining methods in pathological diagnosis of fungal infection by Chi-squaretest.Results:1.Among the 21 patients with subdermal fungal infection,14 cases were positive by modified CFW fluorescent staining(66.67%),HE staining 5cases,23.80%),PAS staining 6 cases(28.57%).11 cases(52.38%)were positive by GMS staining.The positive rate of modified CFW staining was significantly higher than that of HE and PAS staining(c2,6.718,5.200,P =0.012,0.029).There was no significant difference in the positive rate between modified CFW fluorescent staining and GMS staining(c2 = 0.693,P = 0.530,P > 0.05).2.Under UV excitation(UV filter),the hyphae and spores were found in subcutaneous tissues infected with sporotrichosis,Candida and unknown species by modified CFW staining method.The background was dark,the morphological characteristics of fungi were clear and obvious,and the morphological characteristics of fungi were clear and obvious.The negative control group had dark background and no fluorescent reaction.3.In the 4 samples with positive fungal components by four staining methods,the morphological characteristics of fungi were clearer and the contrast between modified CFW staining and other staining methods was more obvious than that of other staining methods.Conclusion:Modified CFW fluorescence staining is an accurate method for fungal examination,and it has certain application value in pathological diagnosis of subcutaneous mycosis.