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I. L. Romero, P. L. Ballalai, J. N. Barros, W. R. Silvino; The Use of 1% Toluidine Blue Eyedrops in the Diagnosis of Ocular Surface Squamous Neoplasia. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5748.
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To evaluate the use of in vivo toluidin blue stain in the diagnosis of ocular surface squamous neoplasia (OSSN) and correlate the intensity of the stain with the pathological diagnosis.
A prospective study was performed, at the Ocular Oncology unit of the Federal University of Sao Paulo. Patients with conjunctival non pigmented lesions were submitted to clinical evaluation by slit lamp with and without 1% toluidine blue eyedrops and photo documentation. Before the instillation of the dye, proximetacain cloridrate 1% was used. The patients were grouped according to the clinical aspects of the lesions into 3 groups: group 1-patients with OSSN (conjunctival intraepithelial neoplasia and conjunctival squamous cell carcinoma); group 2-patients with premalignant lesions (actinic keratosis) and group 3-patients with benign lesions (pterygium). All patients were submitted to surgery and the pathology to confirm the diagnosis. The digital images were analysed by two masked examiners, who had no previous access to the histopathological results. The photos were classified according to the positivity and intensity of the stain. The intensity was classified into Dark Royal Blue, Pale Royal Blue or Mixed pattern. Methods of statistical analysis were choosen depending on the type of data, with the level of statistical significance set as p<0.05.
Forty-seven patients were included in the study. They were divided into 3 groups according to the histopathological diagnosis: 10 patients had pterygium, 10 patients had premalignant lesions and 27 patients had malignant lesions. Agreement between observers regarding the analysis of the digital photographs for positivity and intensity of the stain was 82.9% (Kappa 0.938). Ninety percent of patients with premalignant lesions and all patients with malignant lesions had a positive stain by the 1% toluidine blue. One patient had a positive stain but the pathology revealed a benign lesion (false-positive). The statistical analysis showed a sensitivity of 100%, a specificity of 90%, a positive predictive value of 96.4% and negative predictive value of 100%, with a statistical significance by the Fisher’s exact test (p<0.0001). We did not find a correlation between intensity of the stain and histopathological diagnosis (Spearman r=-0.1125; p=0.6783).
The use of 1% toluidine blue eyedrops is an efficient method for the clinical diagnosis of ocular surface squamous neoplasia and premalignant lesions. Nevertheless, the intensity of the stain is not correlated to degree of malignancy of this tumors.
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