OP06.05: Diagnostic accuracy of modified benign descriptor one in the diagnosis of endometriomas

To evaluate the diagnostic accuracy of the modified benign descriptor one (MBD 1) in the diagnosis of endometriomas. Ambispective observational study based on ultrasound data collected at a University Hospital with a gynecologic oncology unit between 2012 and 2023. Two IOTA-certified level III gynecologists classified adnexal masses using the MBD. The main result was the correct classification of endometriomas, based on the first descriptor of the MBD (MBD 1). Histopathology was used as the diagnostic reference standard. A diagnostic accuracy study was performed. A total of 1,047 adnexal masses were assessed, of which 656 (62.6%) were included when they met the classification criteria for their evaluation based on MBD. 210 masses were diagnosed as endometriomas by the MBD 1, of which 181 (86.2%) corresponded to endometriomas by histopathology. 13.8% (29/210) were false negatives, and the diagnoses that caused confusion were: paratubal cysts with hemorrhage (24%), hemorrhagic corpus luteum (24%), hemorrhagic cysts (21%), serous cystadenofibroma (6.8%), mucinous cystadenoma (6.8%), serous cystadenoma (6.8%), tubo-ovarian abscess (6.8%), and mature cystic teratoma (3.4%). The diagnostic yield for MBD 1 had a sensitivity of 87.86%, specificity of 93.56%, positive predictive value of 86.19%, negative predictive value of 94.39%, and diagnostic accuracy of 91.77%. In our experience, MBD 1 has the ability to adequately classify most endometriomas, which is why it could be a valuable tool in clinical practice.