Coexistence of malignant struma ovarii and Graves' disease

Objective: To report an unusual case of hyperthyroidism from Graves' disease that was coexistent with malignant struma ovarii. Methods: We summarize the clinical history, physical findings, laboratory data, imaging studies, pathologic features, and treatment in a patient with recurrent hyperthyroidism and discuss the incidence of ovarian tumors of various histologic origins, including thyroid tissue (that is, struma ovarii). Results: Five years after diagnosis of Graves' disease and resolution of symptoms with 1 year of antithyroid drug therapy, a 53-year-old woman had recurrence of palpitations, tremors, and weight loss. Results of thyroid function tests showed high total and free thyroxine levels and a low thyrotropin level. Thyroid radioiodine uptake was high (69% at 24 hours). Abdominal ultrasound studies disclosed a cystic mass in the right adnexal area. Total abdominal hysterectomy and bilateral oophorectomy revealed a 7.5-cm cystic right ovary that contained a 1.0-cm struma ovarii with a 0.4-cm nodule of follicular variant papillary thyroid carcinoma within it. The patient was treated with methimazole and radioiodine ablation of the thyroid. Three months later, a massive myocardial infarction resulted in her death. Conclusion: The concomitant presence of Graves' disease complicates the management of struma ovarii and raises interesting questions about treatment and prognosis.