Malignant struma ovarii in an 11-year-old girl

Abstract Struma ovarii is a highly specialized form of mature ovarian teratoma in which contains greater than 50% thyroid tissue and absence of uniform diagnostic criteria combined with the rarity of the tumor contributes to the large discrepancy in the reported frequency. When the characteristic features of thyroid carcinoma are present, the lesion is termed malignant struma ovarii. An 11-year-old girl presented with palpitation and right lower pain that was diagnosed with right ovarian mass and was ultimately treated by right abdominal salpingo-oophorectomy. Postoperatively, she was diagnosed with a malignant struma ovarii. The patient was subsequently treated with thyroidectomy and is currently disease free. Malignant struma ovarii is a medical rarity and previous studies have reported cases with struma ovarii in adults and to our best knowledge this is the first describing struma ovarii in a girl before puberty. Conclusion according to results, Struma ovarii should be considered in the differential diagnosis of female presenting with hyperthyroidism and without clear etiology; and radioactive uptake and scan and thyroglobulin levels can be useful diagnostic tools.