The presence and location of epithelial implants and implants with epithelial proliferation may predict a higher risk of recurrence in serous borderline ovarian tumors: a clinicopathologic study of 188 cases

SummarySerous borderline ovarian tumors have a favorable prognosis, and recurrences are uncommon. The factors influencing recurrence are not fully understood. Epithelial inclusions are identified in serous borderline ovarian tumors and are traditionally referred to as epithelial implants, which often show epithelial proliferation. We investigated whether the presence of epithelial implant and epithelial proliferation portends a higher risk for recurrence of serous borderline ovarian tumors in patients who underwent surgical removal of these tumors. Also examined was whether the anatomical site of epithelial implant and epithelial proliferation was associated with a higher risk of recurrence. One hundred eighty-eight cases of pure serous or predominantly serous borderline ovarian tumors were studied for the presence of epithelial implant and epithelial proliferation, and subsequent recurrences were recorded. The anatomical sites of epithelial implant and epithelial proliferation were compared between serous borderline ovarian tumors with or without recurrence. Statistical analysis was performed using the χ2 test. Epithelial implant was noted in 106 cases (56%), and epithelial proliferation, in 26 cases (14%). Recurrence was identified in 10.4% cases with epithelial implant and 23% cases with epithelial proliferation. Statistical analyses of patients with recurrence showed significant differences in the following groups: epithelial implant versus no epithelial implant (P < .025) and epithelial proliferation versus no epithelial implant (P < .001). Recurrence rates were higher in the epithelial implant and epithelial proliferation groups as compared with no epithelial implant or epithelial proliferation groups. Epithelial implant and epithelial proliferation appear to pose a statistically significantly higher risk of recurrence in serous borderline ovarian tumors as compared with the absence of epithelial implant. Although the anatomical location of such implants was not significantly associated with a higher risk, the presence of epithelial proliferation at multiple sites was more frequently seen in recurrent serous borderline ovarian tumors.