EP23.63: Serous multilocular cystadenoma in a 12‐year‐old patient: a case report

Serous cystadenomas account for 25% of benign ovarian masses on women in reproductive age. In the pediatric population, ovarian neoplasms are uncommon findings, occurring at a rate of 3 cases per 100,000 individuals per year. Epithelial neoplasms account for 5-31% of these cases, with the majority being serous or mucinous cystadenomas. This case involves a 12-year-old patient with no prior medical history who presented to the emergency department with abdominal pain in the right hypochondrium, associated with vomiting, unresponsive to acetaminophen. Abdominal ultrasound revealed a multiseptated cystic lesion in the right adnexa measuring 84x87x44mm with a volume of 189cc, no flow on colour Doppler assessment. The IOTA Adnex 94.7% benign, 5.3% malignant, and 4.1% borderline. The patient was evaluated by the gynecology service, who decided to characterise the lesion with magnetic resonance imaging (MRI) and correlate it with tumour markers, alpha-fetoprotein 1.46, carcinoembryonic antigen 0.56, CA 125 42.6, and Beta HCG less than 0.6. Abdominal and pelvic MRI showed a 9cm multiloculated cyst with multiple thin septa, without solid or fatty components, and no signs of secondary neoplastic involvement in the abdominopelvic cavity. The patient underwent laparoscopic right oophorectomy and resection of the paraovarian cyst without complications. Pathology revealed a multilocular serous cystadenoma. Ovarian neoplasms are uncommon in the pediatric population, and most of them are asymptomatic benign findings. Symptoms that do occur may be caused by transient torsions, as described in this case, manifesting as acute abdominal pain and vomiting, which has been shown to be indicative of torsion. Ultrasonographic diagnosis in girls with acute abdominal pain is a useful tool for ruling out ovarian pathology.