Introduction/Background*Intraoperative frozen section (IFS) is considered a relevant procedure to categorize adnexal lesions as benign, borderline or malignant. The aim of this study is to determine the accuracy of IFS performed in our tertiary referral centre by assessing its correlation with definitive histopathologic diagnosis.

Methodology This retrospective study included 89 patients with adnexal tumours, who consecutively underwent surgery and intraoperative histopathological examination in our Institution between 2017 and 2020. IFS was compared to definitive histopathological diagnosis and sensitivity, specificity, positive predictive value, negative predictive value and accuracy of IFS were determined according to malignancy status, with a 95% confidence interval (CI).

Result(s)*Mean patient age was 56.3 years (SD 14.3) and 53.9% (48/89) were post-menopausal. IFS indicated benign tumours in 60 cases (67.4%), borderline in 12 (13.5%) and malignant in 17 (19.1%). Definitive histopathologic assessment diagnosed benign tumours in 58 cases (65.2%), borderline in 15 (16.9%) and malignant in 16 cases (18%). Concordance between IFS and definitive histopathologic diagnosis was found in 77 cases (86.5%). Overall accuracy of IFS was 92.1% for malignant tumours, 91.0% for benign and 89.9% for borderline.

Conclusion*In our series of patients, in agreement with previously published data, IFS was an important tool in the assessment of adnexal masses, allowing an adequate surgical staging of invasive malignancies. With low positive predictive value, IFS presented limitations in the diagnosis of borderline tumours.