Role of tissue eosinophils in oral Leukoplakia: A pilot study

Tissue eosinophilia in oral squamous cell carcinoma has been well - recognized. Studies have reported both favorable and unfavorable prognoses associated with tissue eosinophils in oral squamous cell carcinoma. However, the role of eosinophils in the development of tumor is still unclear.

The present study was an attempt to elucidate the potential role of tissue eosinophils in oral leukoplakia, a potentially malignant lesion.

To count eosinophils in tissues of normal subjects and oral leukoplakia cases. To compare tissue eosinophil count (TEC) between normal and oral leukoplakia cases. To compare TEC between dysplastic and non-dysplastic cases of oral leukoplakia and to correlate with degree of epithelial dysplasia.

A total of 85 cases (59 cases of oral leukoplakia and 26 normal oral tissues) constituted the study material. Tissue eosinophils were counted in 10 different high- power fields.

Non-parametric tests (Mann-Whitney U-test, Kruskal-Wallis test, Mann-Whitney post hoc analysis and Spearman's correlation statistics).

Mean eosinophil count (MEC) in oral leukoplakia cases was significantly more when compared to normal subjects. MEC in dysplastic cases of oral leukoplakia was significantly more when compared to those without epithelial dysplasia (Mann-Whitney U-test). Furthermore, MEC was directly proportional to the degree of epithelial dysplasia (Spearman's correlation statistics).

TEC may be used as an adjunct to predict the malignant transformation of dysplastic cases of oral leukoplakia. Eosinophilic infiltration in oral dysplastic cases should prompt a thorough evaluation for invasiveness, especially when features of invasion are absent or suspected in smaller biopsy specimens. Use of TEC as a prognostic indicator demands larger sample size and mandates long-term follow-up.