Potential role of increasing number of sections in frozen section diagnosis of ovarian tumors.

OBJECTIVE: To assess the accuracy of intraoperative frozen section of ovarian tumours at our institution and to identify the possible reasons for misdiagnosis.

STUDY DESIGN: Between January 2002 and August 2013, a total of 684 patients were included in the study. Frozen section diagnosis was compared with the final paraffin section diagnosis as the gold standard. The sensitivity, specificity, and positive and negative predictive values of frozen-section diagnosis were calculated for benign, borderline and malignant tumours. Clinicopathological parameters influenced by misdiagnosis were evaluated performing multivariate logistic regression analysis.

RESULTS: The overall accuracy was detected as 96.1%. Frozen-section diagnoses of 26 patients (3.8%) showed discordance. The specificity (99.7%) and PPV (99.4%) of frozen-section diagnosis was highest in the malignant category. In BOTs, diagnostic agreement was observed in 57 of 70 (81.4%) cases. The PPV (81.4%) was lowest for these patients. Tumour diameter of ≥10 cm (OR [95% CI]= 3.0 [1.1 to 8.2]; P=0.030) and mucinous histology (OR [95% CI]= 2.5 [1.0 to 6.2]; P=0.042) were significant predictors of misdiagnosis. With the increase in the number of sections, the accuracy rate of frozen section diagnosis was decreased. While not statistically significant (p=0.361).

CONCLUSION: The number of sections is increased parallel to increase in tumor diameters. On the contrary, the diagnostic accuracy was no significantly increased with an increase in the number of sections. This discrepancy may be associated with falling tumor size per frozen section. A prospective study based on a certain tumour diameter per frozen section may better demonstrate the positive effect of the number of sections.