Background The clear cell borderline ovarian tumor (CCBOT) of the ovary is a rare tumor accounting for less than 1% of BOT. Fewer than 25 cases have been reported in the literature (including details on clinical management and outcomes). The aim of this study was to determine the prognosis of a series of CCBOTs collected in 2 reference centers.

Patients and Methods This was a retrospective review of patients with CCBOT treated or referred to our institutions. A centralized histological review by a reference pathologist and data on the clinical characteristics, management, and outcomes of patients were required for inclusion.

Results Twelve patients were identified between 2000 and 2010. The median age of patients was 68 years (range, 36–83 years). Two had been treated conservatively and 9 radically (data unknown in 1). The tumor was unilateral in 11 cases. All patients had stage I disease. All cases were CCBOT with an adenofibromatous pattern. Stromal microinvasion or intraepithelial carcinoma was histologically associated in 2 and 3 cases, respectively. Four of the 12 patients had synchronous endometrial disorders (but no endometrioid carcinoma). No cases were histologically associated with endometriosis. Four patients were lost to follow-up. Among 8 other patients, after a median period of 28 months (range, 2–129 months), no recurrence had occurred (1 patient had died of another disease).

Conclusion Clear cell borderline ovarian tumor carries a good prognosis. All tumors are stage I; therefore, surgical staging is not necessary in most of the cases. Conservative treatment could be proposed to young patients, but uterine curettage would then be required in cases of uterine preservation.