EP231/#1099 Discrepancies Between Frozen and Final Diagnosis in the Evaluation of Mucinous Borderline Ovarian Tumors

Objectives The distinction of ovarian Mucinous Borderline Tumors (MBT) from carcinomas remains the greatest challenge for pathologists. The aim of the work was to assess concordance between the response of extemporaneous examination (EE) and the final diagnosis of MBT. Methods Our study was retrospective including 37 cases of primary ovarian MBT, diagnosed at the Pathology Department of Salah Azaiez Institute from 1992 to 2019. We included in our study all patients who presented with a primary MBT on a surgical specimen and who had an EE of the tumor. Results The EE showed a borderline tumor in 27 cases (the exact diagnosis), a benign tumor in six cases, and a carcinoma in one case. In two cases, it was necessary to wait for the final result after inclusion in paraffin. Finally, in one case, the EE could not be concluded due to extensive necrosis. The EE/definitive examination concordance rate was about 73%. Conclusions The EE is a valuable aid in guiding the therapeutic decision, but it is difficult due to the bulky and heterogeneous nature of these tumours. According to the literature, the concordance between the EE and the final diagnosis of borderline tumors varies from 44 to 70%. This examination is quite effective in excluding the diagnosis of benign tumor and often responds that the tumor is ‘at least’ borderline.