Introduction/Background*Mucinous borderline ovarian tumors (MBT) are characterized by an epithelial proliferation similar to those of well-differentiated adenocarcinomas but are distinguished by the absence of stromal invasion. They are often difficult to diagnose histologically. On the one hand, the invasion of the stroma is not always easy to highlight, and on the other hand, the indirect criteria of invasion are not unanimously accepted. The work aims to specify the pathological and clinical features and to highlight the prognostic factors of these tumors.

Methodology Our study was retrospective and descriptive including 49 cases of primary borderline mucinous tumors of the ovary, diagnosed at the Department of Anatomical Pathology and Cytology of Salah Azaiez Institute, for a period of 27 years, going from 1992 to 2019.

Result(s)*The mean age of our patients was 48 years old. Histologically, the cases were divided into 34 cases of pure MBT, 13 cases with intraepithelial carcinoma, and 2 cases associating an intraepithelial carcinoma with microinvasion. The majority of our cases were classified FIGO I and only one case was FIGO III. 14 patients received conservative treatment and 32 received radical treatment. The treatment wasn’t specified in 3 patients. The progress was good in the majority of cases. Only one patient had a contralateral recurrence after a follow-up period of 3 years. There was no significant difference regarding the risk of recurrence and risk factors such as age, gestation, hormonal contraception, hormonal status, FIGO stage, presence of peritoneal pseudomyxoma, intraepithelial carcinoma, and microinvasion.

Conclusion*The prognosis of TMBL depends closely on their FIGO stage, stage I tumors have a good prognosis. The presence of intraepithelial carcinoma does not influence their prognosis. However, it is necessary to multiply samples to avoid missing a carcinomatous focus with an anarchic invasion of the stroma which constitutes a poor prognosis factor.