Comparison of toluidine blue 1% staining patterns in cytopathologically confirmed ocular surface squamous neoplasias and in non-neoplastic lesions.

PURPOSE: To evaluate the role of toluidine blue (TB) staining patterns in diagnosis of ocular surface squamous neoplasia (OSSN) in comparison to that of impression cytology.

METHODS

TB 1% dye was applied to different ocular surface lesions, followed by impression cytology (IC). Dye distribution, intensity, and pattern of uptake by the lesion were scored and total score ≥5 was considered "positive TB staining". The TB results were then compared with those using IC to determine the presence of cellular atypia.

RESULTS

The study enrolled 88 eyes of 82 patients. IC demonstrated cellular atypia in 50 (56.8%) cases. Forty-three of 45 "TB-positive" eyes (95.51%) had cellular atypia on IC (p < 0.001). Sensitivity and specificity of TB in identifying OSSN were 86% and 94.74%, respectively, with positive and negative predictive values of 95.56% and 83.72%. TB staining intensity of dark blue and/or mixed types and stippled pattern of TB staining were strongly correlated with dysplastic changes in IC (P ˂ 0.001). TB staining distribution whether in form of diffuse, patchy or scattered eyes with atypia did not significantly differ from those without atypia in IC (P = 0.172).

CONCLUSION

The sensitivity and specificity of TB vital dye in diagnosing OSSN can be increased by focusing on color intensity and a stippled pattern.