Immunohistochemical assessment of odontogenic tumors using smooth muscle actin - A short study

Context: Odontogenic tumors constitute an unusually diverse group of lesions. They are usually benign, though occasionally locally invasive, slow-growing neoplasms, exhibit various biological behaviors. The biological behavior of the odontogenic tumors is contributed by many factors of which stromal myofibroblasts (MF) have the potential to facilitate progression of odontogenic tumors which could contribute to the same. The presence of alpha smooth muscle action (αSMA) positive myofibroblasts in odontogenic tumors has not been thoroughly investigated. Only a few studies in odontogenic tumors are available in English literature. The present study is focused on the same, assessing the presence of stromal myofibroblasts in odontogenic tumors by expressing SMA immunohistochemically. Aims: To assess the expression of α SMA, immunohistochemically, in different odontogenic tumors namely follicular ameloblastoma, ameloblastic fibro-odontoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor and odontogenic myxoma; and correlate it to their aggressive biological behavior. Materials and Methods: Formalin fixed paraffin wax embedded tissue from four follicular ameloblastomas (FA), four ameloblastic fibro-odontomas (AFO), four adenomatoid odontogenic tumors (AOT), four calcifying epithelial odontogenic tumors (CEOT) and four odontogenic myxomas (OM) were selected randomly. 4µm sections were made and were assessed immunohistotochemically for αSMA. Results: Immunohistochemically, reactivity to αSMA was restricted around the blood vessels in FA and AFO cases whereas moderate reactivity was exhibited in AOT and CEOT cases; and intense reactivity in OM cases. Conclusion: The high frequency of stromal MF in known aggressive odontogenic tumors implies that MF can contribute to the biological behavior of these odontogenic lesions. The agents that control stromal MF can be used as an aid to reduce extensive and multilating surgery in cases of remarkably aggressive odontogenic tumors.