The purpose of this was to evaluate accuracy of frozen section diagnosis for ovarian tumors according to histologic type and malignant potential.

We compared the frozen section and final diagnosis of patients with ovarian tumors from April 2001 to April 2006. Of these 1138 cases, 628 cases (55.2%) were epithelial ovarian tumors. Benign, borderline, and malignant epithelial tumors were 380 (60.5%), 87 (13.9%), and 161 (25.6%) cases. The accuracy of frozen section diagnosis was analyzed according to histologic type and malignancy potential.

The overall accuracy of frozen section diagnosis was 93.9%. The accuracy for benign, borderline, and malignant tumors were 93%, 92%, and 98%, respectively. The accuracy of frozen section diagnosis was significantly low in mucinous tumors and borderline malignant tumors. However the borderline malignancy was the only independent factor associated with the inaccuracy of frozen section diagnosis (OR: 12.2, 95% CI: 6.5-23.1). The sensitivity for immature teratoma was as low as 63.6%.

Our data shows that the accuracy is low in mucinous tumors, borderline tumors, and immature teratomas and the borderline malignancy is independent factor associated with inaccuracy of frozen section diagnosis.