Background: Mucinous cystadenoma of the ovary constitutes about 15% of ovarian tumors. It is more common in women between 20 and 40, but is rare in teenagers and exceptional in pre-menstrual girls. Malignant transformation is possible in 5-10% of cases. Spontaneous or iatrogenic breaks are more common. It makes the different diagnosis of pseudomixoma peritonei more difficult.
Case report: A 13-year-old girl came to the National Cancer Institute "Regina Elena" of Rome, with increasing abdominal distension over 2 months. The abdominal mass was removed and a left salpingo-oophorectomy was performed. Histological examination of the mass revealed a 40-cm diameter mucinous cystadenoma of the ovary.
Conclusion: The rapid enlargement of the ovarian mass, the young age and the difficulty of certain pre-operative diagnosis, make this case interesting. Management of this pathology and fertility-conserving treatment need careful follow-up because of the possibility of recurrence in the remaining ovary.