Role of MRI in characterizing serous borderline ovarian tumor and its subtypes: Correlation of MRI features with clinicopathological characteristics

This study aimed to investigate the diagnostic value of MRI in serous borderline ovarian tumor (SBOT), and to determine the MRI features of SBOT and their correlations with clinicopathological characteristics.A total of 121 patients suspected of SBOT by preoperative MRI and then underwent surgery at our hospital were retrospectively reviewed. The accuracy of MRI in diagnosing SBOT was assessed. MRI features of the SBOT subtypes were compared and their correlations with clinicopathological characteristics were evaluated.SBOT was confirmed by postoperative pathology in 95 patients, including 77 patients with conventional SBOT (SBOT-C) and 18 patients with micropapillary SBOT (SBOT-MP). The accuracy of MRI in diagnosing SBOT was 87.6%. Three MRI morphological patterns of SBOT were identified: (i) mainly solid, (ii) mainly cystic, and (iii) mixed. Branching papillary architecture and internal branching (PA&IB) structures corresponding to multiple branching papillary projections and internal fibrous stalks in tumors were observed in 69.7% of SBOTs on T2-weighted images. MRI findings were consistent with postoperative pathology. Compared with SBOT-C, patients with SBOT-MP were more likely to display elevated cancer antigen 125, bilateral tumors, peritoneal implantation, lymph node metastasis, and advanced tumor staging. No significant differences were observed in MRI features between SBOT-C and SBOT-MP groups.MRI has good performance in diagnosing SBOT. MRI findings of SBOT are consistent with clinicopathological characteristics. The PA&IB structure is the characteristic MRI finding of SBOT. Compared to SBOT-C, SBOT-MP tends to display more aggressive clinical behavior, but their MRI features are similar.