A Histopathological and Immunohistochemical Study on Epithelial Proliferative Activity of Adenomatoid Odontogenic Tumor with Special Reference to Comparison with Ameloblastoma

Adenomatoid odontogenic tumor (AOT), which is hitstopathologically composed of pseudoductal cells intermingled with polygonal cells, is a rare odontogenic lesion. On the other hand, ameloblastoma (AM) which tends to grow slowly is most common odontogenic tumor of the jaws. The aim of this study was to compare with the proliferative activity in epithelium of AOT and AM. In addition, the role of cellular proliferation in the pseudoductal cells and polygonal cells of AOT was immunohistochemically and histochemically investigated using several proliferative markers as follows : Ki-67, PCNA and AgNORs. These labelling indexes were calculated in them. The mean Ki-67 and PCNA labeling indexes in AOT were statistically lower than those in AM (p<0.05). And about AOT, the mean Ki-67 labeling index in pseudoductal cells was statistically higher than that in polygonal cells (p<0.05). The present study showed the difference proliferative activity between pseudoductal cells and polygonal cells might depend on cell differentiation.