Objective:

To present the case of a premenarchal female patient diagnosed with borderline ovarian tumor.

Materials and methods:

We present the case of a female patient with a mass dependent on the right ovary, with diagnosis of a borderline ovarian tumor by tumoral markers and histopathological confirmation.

Results:

We performed precision surgery with fertility preservation. The patient had a satisfactory postoperative period and was discharged on the third day without complications.

Conclusions:

Borderline ovarian tumors are infrequent in the pediatric population. These tumors have a good prognosis and high survival rates with adequate diagnosis and surgical management to preserve fertility.