The incidence of ovarian tumors is low in the pediatric age group, accounting for around 1%–5% of solid tumors. In contrast to adults, the most common ovarian tumors in children are germ cell tumors, and cases of borderline cystadenoma are rare.1,2

We present the case of a female patient aged 13 years with a giant borderline mucinous cystadenoma of the ovary. The patient presented with abdominal pain, nausea, vomiting and a palpable mass. The sonographic and CT findings suggested cystadenoma rather than cystadenocarcinoma (Fig. 1). Tumor markers were normal. The patient underwent a midline laparotomy and left salpingo-oophorectomy, which revealed a multilocular cystic neoplasm of irregular consistency and mucinous content weighing 7 kg (Figs. 2 and 3). The microscopic examination of the specimen revealed several solid foci of atypical cells compatible with borderline mucinous cystadenoma, as it met the criteria of nuclear stratification into two to three layers but without stromal invasion.3 We must underscore the importance of the histological analysis in the definitive diagnosis, as it allows differentiation between benign, borderline and malignant tumors. The cytologic evaluation was negative and the postoperative outcome was favorable, without need of adjuvant treatment.

Figure 1.

Coronal CT scan: multilocular trabeculated cystic mass measuring 34 cm × 25 cm × 16 cm.

Figure 2.

Intraoperative image: giant ovarian mass occupying the entire peritoneal cavity.

Figure 3.

Gross appearance: multilocular cystic mass with mucinous contents and solid foci revealed upon cutting.

Borderline mucinous cystadenoma is a rare tumor in children that clinicians ought to consider in the presence of an ovarian mass, as early diagnosis and correct surgical planning enable satisfactory outcomes.