Expression of CK14 and vimentin in adenomatoid odontogenic tumor and dentigerous cyst

BACKGROUND: Origin of adenomatoid odontogenic tumor (AOT) has long been a controversy, and the issue of it being a neoplasm or hamartoma was a subject of debate for a long time. Earlier it was grouped under a mixed group of odontogenic tumors considering the varying degrees of inductive changes. Recently, the WHO classification states that the presence of hard tissue within AOT was not due to induction but was rather a metaplastically produced mineralization and hence the tumor was reclassified under a group of tumors arising from odontogenic epithelium. This study is an attempt to identify if both epithelial (cytokeratin 14 [CK14]) and mesenchymal (vimentin) markers are expressed in the follicular and extrafollicular variants of AOT and to compare the expression with dentigerous cyst (DC) as this cyst is known to arise from reduced enamel epithelium which expressed CK14. This is done to possibly relate the origin of AOT with reduced enamel epithelium. AIMS AND OBJECTIVES: To study, analyze and correlate the expression of CK14 and vimentin in AOT and DC. MATERIALS AND METHODS: Retrospective study on paraffin embedded tissues. Sixteen cases of AOT and 15 cases of DC were retrieved from the departmental archives and subjected to CK14 and vimentin immunostaining. STATISTICAL METHODS: Measures of central tendency was used to analyze the results. RESULTS AND OBSERVATIONS: Ninety percent of cases of follicular AOT (FAOT) and 100% cases of extra-follicular AOTs (EAOTs) showed positivity for CK14 and all cases of DC showed positivity for CK14. Vimentin was positive in 44% and negative in 56% cases of both FAOT and EAOT taken together. CONCLUSION: The CK14 expression profile in AOT and DC supports its odontogenic epithelial specific nature. The possible role of reduced enamel epithelium and dental lamina in histogenesis of AOT and DC is strongly evident by their CK14 expression pattern.