Accuracy of intraoperative frozen section in the evaluation of patients with adnexal mass: retrospective analysis of 748 cases with multivariate regression analysis.

OBJECTIVE: To evaluate the accuracy of intraoperative frozen section in the evaluation of patients with adnexal mass and to define the clinicopathological factors associated with misdiagnosis during frozen section evaluation.

METHODS: The clinicopathological data of patients who underwent exploratory laparotomy for adnexal mass were reviewed. Results of the intraoperative frozen section and permanent histology reports were compared. Univariate and multivariate analyses were performed to reveal factors associated with misdiagnosis.

RESULTS: The study group consisted of 748 patients. Of these patients, 509 (68.0%) had benign, 43 (5.7%) had borderline, 196 (26.2%) had malignant histological diagnosis at permanent section. The overall agreement between intraoperative frozen section and permanent pathology was 96.8%. Twenty four out of 745 cases (3.8%) were misdiagnosed by frozen section. Univariate analysis showed that borderline histology (p < 0.0001) and tumor size larger than 10 cm (p = 0.012) were associated with misdiagnosis. According to multivariate analysis, borderline histology (OR: 22.6, p < 0.0001) was the only independent predictor for misdiagnosis during frozen examination.

CONCLUSION: The frozen section evaluation of the adnexal mass is highly accurate. However, tumor size greater than 10 cm and borderline histology are the factors that adversely influence the accuracy of intraoperative frozen section. Clinicians must be aware of these pitfalls during intraoperative decision making following frozen section report.