Struma Ovarii: A Rare Presentation in a Paediatric Patient

Abstract

Struma Ovarii (SO) is a rare form of teratoma of ovary containing predominantly thyroid tissue, usually comprising more than 50% of the overall mass. It accounts for 1% of all ovarian tumours in adults. Due to its rare presentation in paediatric age group, the exact incidence is not known.The association of SO with hyperthyroidism has been noted in approximately 8% of cases. Radiological evaluation helps in preliminary diagnosis of a complex ovarian cyst, however, a definitive diagnosis of SO can only be made upon extensive histopathological evaluation. Present report is of SO in a 12-year-old female patient, who initially presented with pain abdomen, vomiting and hyperthyroidism with mildly elevated thyroid hormones Triiodothyronine (T3) and Tetraiodothyronine (T4). Magnetic Resonance Imaging (MRI) whole abdomen showed evidence of right-sided dermoid with mild ascites. An exploratory laparotomy was done followed by right ovarian cystectomy and histopathology revealed a mature teratoma predominantly comprising of thyroid tissue (>90% of total ovarian mass), thereby confirming the diagnosis of SO. After one month of surgical resection, the patient’s thyroid profile showed decrease in fT3 and fT4 levels. The index case highlights the unusual occurrence of SO in a paediatric patient along with the role of an extensive histopathological evaluation in diagnosis of the same.