Immunohistochemical Analysis of Unicystic Ameloblastoma and Dentigerous Cyst

Abstract

Background: Diagnosis of odontogenic cystic lesions is challenging because their lining epithelia, which are basically stratified squamous epithelia, resemble each other, especially when they become hyperplastic from an inflammatory reaction. The histological distinction between unicystic ameloblastomas (UAs) and certain non-neoplastic odontogenic cysts can be problematic. Thus, Notch 2 expression has been observed in this immunohistochemical study to discriminate reliably and objectively UA from dentigerous cysts (DCs) in routine practice. Literature search has shown that Notch 2 has not been studied in any of the odontogenic lesions to date, and this study is the first of its kind both nationally and internationally. Thus, the aim of this study is to determine whether Notch 2 can be used to discriminate reliably and objectively cystic jaw lesions in routine practice. Materials and Methods: A total of 26 paraffin-embedded tissues of 13 UA and 13 DC were included, and serial 3 or 4 μm sections were produced from paraffin blocks. One section from each tissue was stained with a routine stain, hematoxylin and eosin to re-evaluate the final histopathologic diagnosis and the other section was expended for immunohistochemistry. Results: The Notch 2 immunoexpression in UA and DC tissue sections demonstrated a mixed result. Four cases of DC showed strong expression, whereas two cases of UA strongly expressed Notch 2. Conclusion: Notch 2 can form a reliable marker in differentiating DC from unicystic ameloblastoma. Thus, the study proved the utility of Notch 2 in differentiating unicystic ameloblastoma from DC.