OBJECTIVE

To investigate the histopathologic and clinical characteristics and proliferative activities of calcifying odontogenic cyst (COC).

METHODS

25 cases of COC were reviewed. The expression of proliferating cell nuclear antigen (PCNA) was studied using avidin-biotin peroxidase method and the number of nuclear organizing regions was calculated by means of the argyrophil staining technique in these cases.

RESULTS

The cases were divided into 13 (52%) cysts and 12 (48%) neoplasms. Of the 12 neoplasms, 4 were odontogenic ghost cell carcinoma, with a PCNA labelling index (65.9% +/- 7.3%) significantly higher than that of benign neoplastic variant (45.8% +/- 11.5%, P < 0.05) and cystic variant (29.3% +/- 11.2%, P < 0.01). The AgNOR counts was higher in the carcinomatous than benign or cystic variant.

CONCLUSION

The lesions show considerable diversity in structure and behavior. It is therefore proposed that quantiation of staining for NOR-associated proteins and the PCNA labelling index are diagnostically useful in COC.