Agnor as a marker of malignant transformation in odontogenic keratocysts.

Nucleolar Organizer Region (AgNOR) counts have been reported as a useful, complementary diagnostic tool for several neoplasias. The morphometric evaluation of AgNOR has also been shown to contribute to the detection of incipient cellular alterations. The aim of the present study was to perform a morphometric analysis of AgNOR in keratocysts (KC), and in three rare cases of malignant transformation of keratocysts (KCm) to explore their use as a marker of the process of malignant transformation in this entity. We performed a study of the 3 cases of keratocysts that had suffered transformation into squamous cell carcinoma (SCC) that were available in our files and of 8 cases of solitary keratocysts (KCs). Paraffin sections were silver stained and employed to perform a morphometric analysis of 7 parameters related to number, size and shape of AgNORs. A comparative analysis of the epithelium of solitary keractocyts (KCs), the cystic epithelium adjacent to the area of transformation (KCm) and the epithelium of the SCC cords was performed. The epithelia of KCs and KCm exhibited statistically significant differences for four of the parameters analyzed: nuclear volume (VNUC), single AgNOR volume (VNOR), Total AgNOR per nucleus (TVNOR) and Contour Index of nuclei (CINUC). KCs and SCC exhibited statistically significant differences for all of the parameters. Given the ease with which this technique can be applied to routine histopathological material, we propose AgNOR evaluation as a diagnostic and prognostic aid in cystic entities that are suspected to have a neoplastic potential.