Accuracy of frozen section diagnosis of ovarian borderline tumor

ObjectiveThe objective of this study was to determine the incidence of invasive cancer in ovarian masses diagnosed as borderline tumor (BT) at the time of frozen section.MethodsWe performed a retrospective review of all patients diagnosed with ovarian BT on frozen section (FS) at our institution between 2000 and 2010. Clinical and pathologic data were extracted. Univariate and multivariate analyses were performed using standard two-sided statistical tests.ResultsA total of 120 patients were identified, of which 104 (86.7%) had BT on frozen section that was confirmed on final pathology. In 15 (12.5%) patients, BT was diagnosed on FS but was reclassified as invasive cancer on final pathology. One patient (0.8%) had BT on FS but benign pathology on final diagnosis. Histologies included serous in 79 (65.8%), seromucinous in 13 (10.8%), mucinous in 21 (17.5), endometrioid in 5 (4.2%), and clear cell in 2 (1.7%) patients. Reclassification of pathologic diagnosis was related to histologic subtype, but only for endometrioid and clear cell tumors (P < 0.001). The rate of invasive cancer for serous micropapillary tumors on frozen section was 42.8% compared with 2.8% for serous non-micropapillary tumors (P < 0.001). Tumor size > 8 cm was associated with a 22.4% incidence of invasive cancer on final pathology compared to 3.2% in tumors ≤ 8 cm (P = 0.004).ConclusionComprehensive surgical staging can be considered in BT > 8 cm in diameter, as well as those with micropapillary serous, endometrioid, and clear cell histology diagnosed at the time of frozen section analysis.

► A study evaluating accuracy of FS diagnosis of ovarian borderline tumors.
► Tumor size and histology were significant predictors of underdiagnosis.
► Accurate diagnosis of micropapillary features on FS is critical.