Tissue eosinophilia in head and neck squamous neoplasia: an update

Eosinophils are multifunctional granulocytes that play an imperative role in health and disease. They have also been found to be a crucial component of peri- and intratumoral inflammatory infiltrate. Tumor-associated tissue eosinophilia (TATE) has been observed and described in many tumors, including head and neck neoplasia. The process of eosinophil recruitment and its function in tumors has not been exactly defined yet. Correlation of tissue eosinophilia with prognosis has shown variable results ranging from favourable to unfavourable prognosis or even having no influence on patients outcome. Eosinophils are hypothesized to have tumor defensive as well as tumor promotive function. This dichotomous role of tissue eosinophilia with regard to prognosis has also been noted in head and neck neoplasia and premalignancies. So, the present review attempts to discuss TATE and its possible pros and cons in head and neck neoplasia.