Coexistence of Graves' disease and struma ovarii: Case report and literature review

We report a rare case of Graves' disease associated with struma ovarii. A 2 6-year-old Japanese woman had preexisting Graves' disease and was positive for TSH receptor antibody. She had been on antithyroid medication at presen tation. She noted a mass in the lower left abdomen, which was diagnosed as a left struma ovarii by radiological work-up including computed tomography, magnetic resonance imaging and scintigraphy. The surgically excised terato matous tumor, containing cystic spaces with thyroid tissue, was histologica lly proved to be struma ovarii. Since thyroid function tests and TSH recept or antibody did not change after surgery, her hyperthyroidism was considere d to be due to Graves' disease. Our case was diagnosed as struma ovarii bef ore surgery using various imaging studies.